A method for improving the conversion effect of nitrite nitrogen in the half-way denitrification process

Abstract

The present invention discloses a method for improving the conversion effect of nitrite nitrogen in a half-denitrification process, the method comprising the following steps: inoculating denitrifying bacteria for activation culture, inoculating the activated bacterial agent in a reactor, adding sulfur-nitrogen wastewater, adjusting the sulfur-nitrogen molar ratio in the reactor to 0.675-6:1, and the carbon-nitrogen mass ratio to 1.02-2.04:1, and performing a half-denitrification reaction under anoxic conditions. In the present invention, by adding sulfur-nitrogen wastewater and adjusting the sulfur-nitrogen molar ratio and carbon-nitrogen mass ratio in the system, and performing a half-denitrification reaction under anoxic conditions, not only can the denitrification effect of denitrifying bacteria be effectively regulated and controlled, and the conversion effect of nitrite nitrogen in the half-denitrification process can be improved, but also the generation rate and conversion rate of nitrite nitrogen in the system can be effectively controlled, and then a stable and efficient electron acceptor can be provided for the half-denitrification-anaerobic ammonia oxidation process according to actual needs, which is ultimately conducive to achieving efficient and deep denitrification of sewage.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage biological treatment, and in particular relates to a method for improving the conversion effect of nitrite nitrogen in a half-denitrification process. Background Art

[0002] In recent years, the discharge of high-nitrogen and high-sulfur wastewater has seriously polluted groundwater, river water, lake water and other surface water, among which groundwater is particularly serious. Since nitrate nitrogen has high solubility and good stability in water, it is difficult to form co-precipitation or adsorption and be removed, so it is easy to spread. The nitrate content of tap water in many places has seriously exceeded the standard, which will not only endanger human health, but also damage the ecological environment. Nitrate nitrogen (NO3 - -N) enters the human body and is converted into nitrite nitrogen (NO2 - -N), in which nitrite will combine with protein, which will not only affect the transfer of oxygen and other functions, causing hypoxic asphyxiation and fainting, but also form a series of strong carcinogens that are extremely harmful to human health and cause cancer if ingested for a long time. Excessive nitrogen in natural water bodies will cause eutrophication, black and smelly water bodies, and cause algae to multiply in large numbers, resulting in algal blooms and red tides, posing a threat to environmental protection. High-nitrogen and high-sulfur wastewaters such as garbage leachate and leather wastewater have high nitrate nitrogen concentrations, low carbon-nitrogen ratios, high toxicity, and difficulty in handling. Therefore, it is extremely important to prevent and control nitrate nitrogen in high-nitrogen and high-sulfur wastewater. Finding a set of efficient solutions to reduce the nitrate nitrogen content in wastewater has become a hot issue in sewage treatment.

[0003] The existing high-nitrogen and high-sulfur wastewater treatment process usually directly reduces nitrate nitrogen to N2 and converts sulfate into elemental sulfur, but aeration and additional sulfide addition are required during the entire process, which is complex and costly, limiting the widespread use of the process. The anaerobic ammonium oxidation process can effectively save aeration and carbon source costs and greatly shorten the intermediate steps to carry out efficient denitrification, and how to provide stable nitrite for anaerobic ammonium oxidizing bacteria has become an urgent problem to be solved. However, in the existing anaerobic ammonium oxidation process, the generation rate and conversion rate of nitrite nitrogen are difficult to effectively control, which makes the overall denitrification effect of the anaerobic ammonium oxidation process still poor. Therefore, how to obtain a method to improve the conversion effect of nitrite nitrogen in the half-denitrification process is of great significance for achieving deep denitrification of nitrate nitrogen wastewater. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for improving the conversion effect of nitrite nitrogen in the half-way denitrification process.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for improving the conversion effect of nitrite nitrogen in a half-denitrification process comprises the following steps:

[0007] S1. Inoculating denitrifying bacteria into an activation culture medium for activation culture to obtain an activated bacterial agent;

[0008] S2. Inoculate the activated bacterial agent into the reactor, add sulfur-nitrogen-containing wastewater, adjust the sulfur-nitrogen molar ratio in the reactor to 0.675-6:1 and the carbon-nitrogen mass ratio to 1.02-2.04:1, and carry out a half-denitrification reaction under anoxic conditions.

[0009] The above method is further improved and further comprises the following steps:

[0010] S3. According to the sulfur-nitrogen molar ratio in the reactor, the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the maximum average removal rate of nitrate nitrogen is combined to obtain the maximum average removal rate of nitrate nitrogen in the reaction system; the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate nitrogen removal rate is shown in formula (1);

[0011] y1=0.695×x1+5.607 (1);

[0012] In formula (1), y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , x1 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9765.

[0013] The above method is further improved and further comprises the following steps:

[0014] S4. According to the sulfur-nitrogen molar ratio in the reactor, the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate-nitrogen removal rate is combined to obtain the nitrate-nitrogen removal rate in the reaction system; the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate-nitrogen removal rate is shown in formula (2);

[0015] y2=-0.704×x2+80.602 (2);

[0016] In formula (2), y2 is the nitrate nitrogen removal rate, in %, x2 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9973.

[0017] The above method is further improved and further comprises the following steps:

[0018] S5. According to the removal rate and removal rate of nitrate nitrogen, the linear regression equation of the removal rate, removal rate and sulfur-nitrogen molar ratio in the reactor is combined to obtain the sulfur-nitrogen molar ratio in the reaction system; the linear regression equation of the removal rate, removal rate and sulfur-nitrogen molar ratio in the reactor is shown in formula (3);

[0019] X=-1.922×Y1^0.5-1.765×Y2+146.8753 (3);

[0020] Where X is the sulfur-nitrogen molar ratio, and Y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , Y2 is the nitrate nitrogen removal rate, unit is %, correlation coefficient R 2 =0.9987.

[0021] The above method is further improved, in step S2, when the sulfur-nitrogen molar ratio in the reactor is 0.675-2.5:1, the half-denitrification reaction time is ≥45h; or, when the sulfur-nitrogen molar ratio in the reactor is 2.5-6:1, the half-denitrification reaction time is 5h-45h.

[0022] The above method is further improved, in step S2, the sulfur-nitrogen-containing wastewater is at least one of landfill leachate, leather wastewater, and pharmaceutical wastewater; the sulfur-nitrogen-containing wastewater contains nitrate, thiosulfate, carbonate and potassium salt, the concentration of nitrate in the sulfur-nitrogen-containing wastewater is 0.911 g / L, the concentration of thiosulfate is 1.329 g / L~10.637 g / L, the concentration of carbonate is 1 g / L, and the concentration of potassium salt is 0.636 g / L, the nitrate is NaNO3, the thiosulfate is Na2S2O3·5H2O, the carbonate is NaHCO3, and the potassium salt is KCl.

[0023] The above method is further improved, in step S2, the volume ratio of the activated bacterial agent to the sulfur-nitrogen-containing wastewater is 0.1-0.15:1, and the anoxic condition is the continuous introduction of nitrogen.

[0024] The above method is further improved, in step S1, the activation culture medium contains the following ingredients: 10.0 g / L peptone, 5.0 g / L yeast powder, 5.0 g / L sodium chloride; the pH value of the activation culture medium is 6.8-7.2.

[0025] The above method is further improved, in step S1, the temperature of the activation culture is 25° C. to 29° C., and the time of the activation culture is 3 days to 5 days.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] In view of the defects that the conversion effect of nitrite nitrogen in the existing anaerobic ammonium oxidation process is difficult to effectively control, the present invention creatively proposes a method for improving the conversion effect of nitrite nitrogen in the half-denitrification process. In the culture system of denitrifying bacteria, by adding sulfur-nitrogen wastewater and adjusting the sulfur-nitrogen molar ratio in the system to 0.675-6:1 and the carbon-nitrogen mass ratio to 1.02-2.04:1, and carrying out a half-denitrification reaction under anoxic conditions, not only can the denitrification effect of denitrifying bacteria be effectively controlled and the conversion effect of nitrite nitrogen in the half-denitrification process be improved, but also the generation rate and conversion rate of nitrite nitrogen in the system can be effectively controlled, and then a stable and efficient electron acceptor can be provided for the half-denitrification-anaerobic ammonium oxidation process according to actual needs, and finally efficient and deep denitrification of sewage can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The graph is a graph showing the change in nitrate nitrogen concentration during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0029] Figure 2 This is a graph showing the change in average nitrate nitrogen removal rate during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0030] Figure 3 This is a graph showing the change in nitrate nitrogen removal rate during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0031] Figure 4 This is a graph showing the change in instantaneous removal rate of nitrate nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0032] Figure 5 The graph is a graph showing the change in nitrite nitrogen concentration during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0033] Figure 6 This is a graph showing the average generation rate of nitrite nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0034] Figure 7 The graph is a variation of the generation rate of nitrite nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0035] Figure 8 This is a graph showing the instantaneous generation rate of nitrite nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention.

[0036] Fig. 9 It is a quantitative curve diagram of the sulfur-nitrogen ratio and the conversion of nitrate nitrogen in the half-denitrification reaction process of the present invention.

[0037] Fig.10 It is a quantitative model diagram of the sulfur-nitrogen ratio and the conversion of nitrate nitrogen during the half-denitrification reaction of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0039] Embodiment 1:

[0040] A method for improving the conversion effect of nitrite nitrogen in a half-denitrification process of the present invention comprises the following steps:

[0041] (1) Inoculate the denitrifying bacteria into an activation medium and culture them independently at 27°C for 3 to 5 days to obtain an activated bacterial agent. The activation medium contains the following components: 10.0 g / L peptone, 5.0 g / L yeast powder, and 5.0 g / L sodium chloride; the pH of the activation medium is 7.0±0.2.

[0042] The denitrifying bacteria used in this embodiment is the Ciceribacter thiooxidans strain in Chinese patent document CN115820466A.

[0043] (2) KCl, NaNO3, Na2S2O3·5H2O, and NaHCO3 were added to water to obtain a mixed solution, in which the concentration of KCl was 0.636 g / L, the concentration of NaNO3 was 0.911 g / L, the concentration of Na2S2O3·5H2O was 1.435 g / L, and the concentration of NaHCO3 was 1 g / L. The mixed solution was used as a simulation of sulfur-nitrogen wastewater.

[0044] (3) The activated bacterial agent was inoculated into the reactor at a volume ratio of 0.1:1 to the simulated sulfur-nitrogen-containing wastewater, and the simulated sulfur-nitrogen-containing wastewater was added to adjust the sulfur-nitrogen molar ratio (i.e., M(S2O3 2- )∶M(NO3 - )) is 0.675:1, the carbon-nitrogen mass ratio (i.e. the mass ratio of NaHCO3-C and NaNO3-N) is 1.02:1, N2 is introduced, and the half-denitrification reaction is carried out at 27°C for 100 hours. During the half-denitrification reaction, the pH value of the system is controlled at 7.0-8.0.

[0045] Embodiment 2:

[0046] A method for improving the conversion effect of nitrite nitrogen in the half-denitrification process of the present invention is basically the same as the method in Example 1, except that in step (2), the concentration of Na2S2O3·5H2O is 2.658 g / L, and the sulfur-nitrogen molar ratio in the reactor is adjusted to 1.25:1.

[0047] Embodiment 3:

[0048] A method for improving the conversion effect of nitrite nitrogen in the half-denitrification process of the present invention is basically the same as the method in Example 1, except that: in step (2), the concentration of Na2S2O3·5H2O is 5.316 g / L, and the sulfur-nitrogen molar ratio in the reactor is adjusted to 2.5:1.

[0049] Embodiment 4:

[0050] A method for improving the conversion effect of nitrite nitrogen in the half-denitrification process of the present invention is basically the same as the method in Example 1, except that in step (2), the concentration of Na2S2O3·5H2O is 10.632 g / L, and the sulfur-nitrogen molar ratio in the reactor is adjusted to 5:1.

[0051] Figure 1 The graph is a graph showing the change in nitrate nitrogen concentration during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 2 This is a graph showing the change in the average removal rate of nitrate nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 3 The figure is a graph showing the change in the removal rate of nitrate nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 4 This is a graph showing the change in the instantaneous removal rate of nitrate nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 5 The graph is a graph showing the change in nitrite nitrogen concentration during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 6 This is a graph showing the average generation rate of nitrite nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 7 The graph is a graph showing the change in the generation rate of nitrite nitrogen during the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention. Figure 8 The instantaneous generation rate of nitrite nitrogen in the second half of the denitrification reaction at different sulfur-nitrogen molar ratios in Examples 1-4 of the present invention is shown in FIG. Figures 1 to 8 It can be seen that when the sulfur-nitrogen molar ratio in the reactor is 0.675:1, 1.25:1, 2.5:1, and 5:1, respectively, after 100 hours of half-way denitrification reaction, the nitrate nitrogen concentration in the wastewater is 27.900 mg·L -1 、29.175mg·L -1、29.575mg·L -1 、34.350mg·L -1 The corresponding removal rates were 80.21%, 79.64%, 78.82% and 77.1%, and the corresponding maximum average removal rates of nitrate nitrogen were 5.845 mg·L -1 ·h -1 、6.596mg·L -1 ·h -1 、7.565mg·L -1 ·h -1 、8.973mg·L -1 ·h -1 At the same time, as the half-way denitrification reaction proceeded, the concentration of nitrite nitrogen gradually increased; when the sulfur-nitrogen molar ratio in the reactor was 0.675:1, 1.25:1, 2.5:1, and 5:1, the corresponding maximum concentrations of nitrite nitrogen were 101.50 mg·L -1 、96.25mg·L -1 、90.75mg·L -1 、98.75mg·L -1 It can be seen that by adding sulfur-nitrogen-containing wastewater and adjusting the sulfur-nitrogen molar ratio in the reactor to 0.675:1, 1.25:1, 2.5:1, and 5:1, it is beneficial to convert nitrate nitrogen into more nitrite nitrogen. In particular, when the sulfur-nitrogen molar ratio in the reactor is 0.675-2.5:1, a more excellent nitrite nitrogen conversion effect can be obtained after 45 hours of half-denitrification reaction, and when the sulfur-nitrogen molar ratio in the reactor is 2.5-6:1, a more excellent nitrite nitrogen conversion effect can also be obtained after 5 hours to 45 hours of half-denitrification reaction. This shows that the method of the present invention can improve the nitrite nitrogen conversion effect in the half-denitrification process.

[0052] In addition, according to Figure 1-4 The removal rate and removal efficiency data of nitrate nitrogen in the second half of the denitrification reaction at different sulfur-nitrogen molar ratios were used to construct the linear regression equations of the sulfur-nitrogen molar ratio in the reactor and the nitrate nitrogen removal rate, and the linear regression equations of the sulfur-nitrogen molar ratio in the reactor and the nitrate nitrogen removal efficiency, respectively. Fig. 9 shown.

[0053] Fig. 9 It is a quantitative curve diagram of the sulfur-nitrogen ratio and the conversion of nitrate nitrogen in the half-denitrification reaction process of the present invention. Fig. 9In the above equation, the sulfur-nitrogen ratio is used as the horizontal axis, and the nitrate nitrogen conversion rate (removal rate) and the maximum average nitrate nitrogen removal rate (removal rate) are used as the vertical axis. Among them, the nitrate nitrogen conversion rate C = (N0-N) / N0, and the nitrate nitrogen removal rate V = N / T (N0: initial nitrate nitrogen concentration, N: nitrate nitrogen concentration, T: reaction time). The linear regression equations of different sulfur-nitrogen ratios and nitrate nitrogen removal rates and removal rates are constructed, as shown in equations (1) to (2).

[0054] y1=0.695×x1+5.607 (1);

[0055] In formula (1), y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , x1 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9765.

[0056] y2=-0.704×x2+80.602 (2);

[0057] In formula (2), y2 is the nitrate nitrogen removal rate, in %, x2 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9973.

[0058] In addition, based on the data of nitrate nitrogen removal rate and removal efficiency under different sulfur-nitrogen ratios, a linear regression equation of nitrate nitrogen removal rate, removal efficiency and sulfur-nitrogen molar ratio in the reactor was constructed, such as Fig.10 shown.

[0059] Fig.10 It is a quantitative model diagram of the sulfur-nitrogen ratio and the conversion of nitrate nitrogen during the half-denitrification reaction of the present invention. Fig.10 In the process, the linear regression equation of nitrate nitrogen removal rate, removal rate and sulfur-nitrogen molar ratio in the reactor was used for regression analysis. The removal rate and removal rate were used as independent variables, and the sulfur-nitrogen ratio was used as the dependent variable to make a binary regression equation. The linear regression equation of nitrate nitrogen removal rate, removal rate and sulfur-nitrogen molar ratio in the reactor was fitted and constructed using Origin software (Excel software can also be used), as shown in formula (3).

[0060] X=-1.922×Y1^0.5-1.765×Y2+146.8753 (3);

[0061] Where X is the sulfur-nitrogen molar ratio, and Y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , Y2 is the nitrate nitrogen removal rate, unit is %, correlation coefficient R 2 =0.9987.

[0062] Depend on Fig. 9The results show that when the maximum removal rate of nitrate nitrogen is 7.554 mg·L -1 ·h -1 When the highest removal rate is 78.630%, it is substituted into formula (3) to obtain a sulfur-nitrogen molar ratio of 2.801. It can be seen that under the premise of taking both removal rate and removal rate into account, the optimal sulfur-nitrogen ratio is 2.801.

[0063] From the above results, it can be seen that in the method of the present invention, in the culture system of denitrifying bacteria, by adding sulfur-nitrogen wastewater and adjusting the sulfur-nitrogen molar ratio in the system to 0.675-6:1 and the carbon-nitrogen mass ratio to 1.02-2.04:1, and carrying out a half-denitrification reaction under anaerobic conditions, not only can the denitrification effect of the denitrifying bacteria be effectively regulated and the nitrite nitrogen conversion effect in the half-denitrification process be improved, but also the generation rate and conversion rate of nitrite nitrogen in the system can be effectively controlled, and then a stable and efficient electron acceptor can be provided for the half-denitrification-anaerobic ammonia oxidation process according to actual needs, and finally efficient and deep denitrification of sewage can be achieved.

[0064] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for improving the conversion effect of nitrite nitrogen in the half-denitrification process, characterized in that: The following steps are involved: S1, inoculating denitrifying bacteria into an activation culture medium, performing activation culture, and obtaining an activated bacterial agent; the denitrifying bacteria is a Thiocyclic Bacillus oxidans strain; S2. Inoculate the activated bacterial agent into the reactor, add sulfur-nitrogen wastewater, adjust the sulfur-nitrogen molar ratio in the reactor to 5:1, and the carbon-nitrogen mass ratio to 1.02-2.04:1, and carry out a half-denitrification reaction under anoxic conditions. The time of the half-denitrification reaction is 45 hours.

2. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to claim 1, characterized in that: The following steps are also included: S3. According to the sulfur-nitrogen molar ratio in the reactor, the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the maximum average removal rate of nitrate nitrogen is combined to obtain the maximum average removal rate of nitrate nitrogen in the reaction system; the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate nitrogen removal rate is shown in formula (1); y1=0.695×x1+5.607(1); In formula (1), y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , x1 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9765.

3. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to claim 1, characterized in that: The following steps are also included: S4. According to the sulfur-nitrogen molar ratio in the reactor, the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate-nitrogen removal rate is combined to obtain the nitrate-nitrogen removal rate in the reaction system; the linear regression equation of the sulfur-nitrogen molar ratio in the reactor and the nitrate-nitrogen removal rate is shown in formula (2); y2=-0.704×x2+80.602(2); In formula (2), y2 is the nitrate nitrogen removal rate, the unit is %, x2 is the sulfur-nitrogen molar ratio, and the correlation coefficient R 2 =0.9973.

4. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to claim 1, characterized in that: The following steps are also included: S5. According to the removal rate and removal rate of nitrate nitrogen, the linear regression equation of the removal rate and removal rate of nitrate nitrogen in the reactor and the sulfur-nitrogen molar ratio is combined to obtain the sulfur-nitrogen molar ratio in the reaction system; the linear regression equation of the removal rate and removal rate of nitrate nitrogen in the reactor and the sulfur-nitrogen molar ratio is shown in formula (3); X=-1.922×Y1^0.5-1.765×Y2+146.8753(3); Where X is the sulfur-nitrogen molar ratio, and Y1 is the maximum average removal rate of nitrate nitrogen, in mg·L -1 ·h -1 , Y2 is the nitrate nitrogen removal rate, unit is %, correlation coefficient R 2 =0.9987.

5. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to any one of claims 1 to 4, characterized in that: In step S2, the sulfur-nitrogen-containing wastewater is at least one of landfill leachate, leather wastewater, and pharmaceutical wastewater; the sulfur-nitrogen-containing wastewater contains nitrate, thiosulfate, carbonate and potassium salt, the concentration of nitrate in the sulfur-nitrogen-containing wastewater is 0.911 g / L, the concentration of carbonate is 1 g / L, and the concentration of potassium salt is 0.636 g / L, the nitrate is NaNO3, the thiosulfate is Na2S2O3·5H2O, the carbonate is NaHCO3, and the potassium salt is KCl.

6. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to any one of claims 1 to 4, characterized in that: In step S2, the volume ratio of the activated bacterial agent to the sulfur-nitrogen-containing wastewater is 0.1-0.15:1, and the anoxic condition is continuous introduction of nitrogen.

7. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to any one of claims 1 to 4, characterized in that: In step S1, the activation medium comprises the following components: 10.0 g / L peptone, 5.0 g / L yeast powder, 5.0 g / L sodium chloride; the pH value of the activated culture medium is 6.8-7.

2.

8. The method for improving the conversion effect of nitrite nitrogen in the half-denitrification process according to any one of claims 1 to 4, characterized in that: In step S1, the temperature of the activation culture is 25° C. to 29° C., and the time of the activation culture is 3 to 5 days.

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