A low-temperature and high-efficiency denitrification method for sulfur autotrophic denitrification driven by regulating electron donors

Abstract

The present invention belongs to the field of biological denitrification technology for sewage treatment, and more specifically to a low-temperature and high-efficiency denitrification method for regulating electron donor-driven sulfur autotrophic denitrification. The present invention is inoculated with seed sludge into a sequencing batch biofilm reactor, and at an ambient temperature of 25-27 DEG C, by regulating the type and concentration of electron donors (carbon source and / or sulfur source), successively through heterotrophic denitrification acclimation treatment, mixed denitrification acclimation treatment and sulfur autotrophic denitrification acclimation treatment, the startup of sulfur autotrophic denitrification denitrification system is achieved; Based on the sulfur autotrophic denitrification denitrification system started, the ambient temperature of the optimized acclimation treatment is 13-15 DEG C, and a sulfur autotrophic denitrification high-efficiency denitrification system suitable for low-temperature environment is obtained, and the total nitrogen removal rate of the system for 62 consecutive days is maintained at more than 97%. The present invention is applicable to various nitrogenous sewage treatment scenes, has significant application value in the sewage treatment of low-temperature areas or low-temperature seasons, and provides a new technical approach for realizing efficient, economical and sustainable development of sewage treatment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment biological denitrification, more specifically, it relates to a low-temperature and high-efficiency denitrification method for regulating and controlling electron donor-driven sulfur autotrophic denitrification. BACKGROUND

[0002] The removal of nitrogen-containing pollutants in sewage has become an important issue in the field of sewage treatment. Traditional biological denitrification processes mainly rely on heterotrophic denitrification, which uses organic carbon sources as electron donors to reduce nitrate to nitrogen gas. However, this method has some limitations, such as the need for a large amount of additional carbon source, which increases the operating cost and increases the amount of carbon emissions. The additional carbon source (such as methanol) in the heterotrophic denitrification process can significantly increase the economic cost and may cause secondary pollution problems. In addition, the decomposition of the additional carbon source in the heterotrophic denitrification process releases carbon dioxide, further exacerbating greenhouse gas emissions. Under low-temperature conditions, the activity of heterotrophic denitrification microorganisms is significantly reduced, resulting in a significant decrease in denitrification efficiency. Especially in winter or cold regions, traditional heterotrophic denitrification processes are difficult to maintain high-efficiency operation, increasing the difficulty and cost of sewage treatment. Therefore, developing a biological denitrification technology that can efficiently denitrify at low temperatures is of great significance to improve the economic efficiency and environmental sustainability of sewage treatment.

[0003] Sulfur autotrophic denitrification is an emerging biological denitrification technology that uses inorganic sulfur compounds such as sulfide as electron donors to reduce nitrate to nitrogen gas under anoxic conditions. Compared with traditional heterotrophic denitrification, sulfur autotrophic denitrification has significant advantages. First, sulfur autotrophic denitrification does not require additional organic carbon sources, thereby reducing operating costs and avoiding carbon dioxide emissions from carbon source decomposition, making it a green and low-carbon biological denitrification technology. The sulfur sources used in sulfur autotrophic denitrification include S 2- , S 0 , S2O3 2- Second, the biomass of sulfur autotrophic denitrification is less than that of heterotrophic denitrification, so using a sulfur autotrophic denitrification system can also reduce the cost of subsequent sludge treatment.

[0004] However, sulfur autotrophic denitrification technology still faces some challenges in practical application. Compared with traditional heterotrophic denitrification, the influent of sulfur autotrophic denitrification does not contain carbon sources, making it difficult for heterotrophic microorganisms to survive, and the microbial community structure is simple, with poor resistance to environmental changes. Therefore, to achieve stable startup of the sulfur autotrophic denitrification system, how to smoothly transition from traditional heterotrophic denitrification to sulfur autotrophic denitrification and adapt to low-temperature environments for efficient denitrification has become a difficult problem to overcome.

[0005] Therefore, how to provide a technology that can efficiently start a sulfur autotrophic denitrification system and maintain high denitrification efficiency at low temperatures has become a difficult problem to overcome in the field. SUMMARY

[0006] The purpose of the present application is to provide a low-temperature and high-efficiency denitrification method for regulating electron donor-driven sulfur autotrophic denitrification. The present application realizes the stable start of sulfur autotrophic denitrification by regulating the type and concentration of the electron donor, and maintains stable and efficient denitrification performance at low temperature, thereby providing a new technical solution for the wastewater treatment field to solve the problems existing in the prior art.

[0007] To achieve the above purpose, the present application provides the following solutions:

[0008] One of the technical solutions of the present application is to provide a low-temperature and high-efficiency denitrification method for regulating electron donor-driven sulfur autotrophic denitrification, which comprises the following steps:

[0009] The seed sludge is inoculated into a biofilm reactor, and the reactor maintains an anaerobic environment. The low-temperature and high-efficiency denitrification of the sulfur autotrophic denitrification system is realized by regulating the type and concentration of the electron donor and the acclimation temperature.

[0010] The electron donor includes a carbon source and / or a sulfur source.

[0011] The step of realizing the low-temperature and high-efficiency denitrification of the sulfur autotrophic denitrification system includes: first, using the carbon source for heterotrophic denitrification acclimation treatment, then using the carbon source and the sulfur source for mixed denitrification acclimation treatment, then using the sulfur source for sulfur autotrophic denitrification acclimation treatment, and finally performing low-temperature acclimation to obtain a low-temperature and high-efficiency denitrification system of the sulfur autotrophic denitrification system.

[0012] The low-temperature and high-efficiency denitrification system of the sulfur autotrophic denitrification system is used for denitrification treatment under low-temperature conditions. The low temperature is 13-15℃.

[0013] The present application gradually guides the microbial community to change from heterotrophic denitrification to sulfur autotrophic denitrification by regulating the concentration of the carbon source and the sulfur source in the influent in stages.

[0014] The heterotrophic denitrification stage is the process in which the denitrifying bacteria take the carbon source as the electron donor, take NO3 - -N as the electron acceptor, and reduce NO3 - -N to N2.

[0015] The mixed denitrification stage is the process in which the denitrifying bacteria take the carbon source and the sulfur source as the electron donor, take NO3 - -N as the electron acceptor, and reduce NO3 - -N to N2.

[0016] The sulfur autotrophic denitrification stage is the process in which the denitrifying bacteria take the sulfur source as the electron donor, take NO3 - -N as the electron acceptor, and reduce NO3 - -N to N2.

[0017] Further, the anaerobic environment maintained in the reactor in the low-temperature high-efficiency denitrification method has a dissolved oxygen concentration of less than 0.02 mg / L, a hydraulic retention time (HRT) of 4±0.5 h, and an ambient temperature of 25-27°C.

[0018] Further, the carbon source includes at least one of sodium acetate, glucose, methanol, and sodium citrate.

[0019] Further, the sulfur source includes at least one of sodium thiosulfate, sulfide, and elemental sulfur.

[0020] Further, the step of the heterotrophic denitrification domestication treatment includes: taking the carbon source as an electron donor, setting the influent parameters of the reactor to C / N=5 and S / N=0, and performing the heterotrophic denitrification domestication treatment; and when the total nitrogen (TN) removal rate is stabilized at more than 97%, the heterotrophic denitrification domestication treatment is completed.

[0021] When the total nitrogen (TN) removal rate is stabilized at more than 97%, it indicates that the heterotrophic denitrification system is successfully started.

[0022] Optionally, the influent parameters specifically include 60±5 mg / L of NO3 - -N and 300±25 mg / L of COD.

[0023] Further, the step of the mixed denitrification domestication treatment includes: after the completion of the heterotrophic denitrification domestication treatment, simultaneously taking the carbon source and the sulfur source as electron donors, setting the influent parameters of the reactor to C / N=1.67 and S / N=3.9, and performing the mixed denitrification domestication treatment; and when the total nitrogen (TN) removal rate is stabilized at more than 98%, the mixed denitrification domestication treatment is completed.

[0024] Optionally, the influent parameters specifically include 60±5 mg / L of NO3 - -N, 100±8 mg / L of COD, and 234±20 mg / L of S2O3 2- -S.

[0025] When the total nitrogen (TN) removal rate is stabilized at more than 98%, it indicates that the microbial community has gradually adapted to the environment with the sulfur source as an electron donor, and the system successfully transitions to the mixed denitrification stage.

[0026] Further, the step of the sulfur autotrophic denitrification domestication treatment includes: after the completion of the mixed denitrification domestication treatment, taking the sulfur source as an electron donor, setting the influent parameters of the reactor to C / N=0 and S / N=5, and performing the sulfur autotrophic denitrification domestication treatment; and when the total nitrogen (TN) removal rate is stabilized at more than 94%, the sulfur autotrophic denitrification domestication treatment is completed.

[0027] Optionally, the parameters of the influent water specifically include 60±5mg / L of NO3 - -N, 300±25mg / L of S2O3 2- -S.

[0028] When the total nitrogen (TN) removal rate is stabilized at more than 94%, it indicates that the sulfur autotrophic denitrification system is successfully started and has high-efficiency denitrification capacity.

[0029] Further, the low-temperature domestication step includes:

[0030] The ambient temperature of the reactor is adjusted to 13-15℃, the influent water parameters of the reactor are set as C / N=0 and S / N=5, and when the total nitrogen removal rate is stabilized at more than 97%, the low-temperature domestication is completed, and a sulfur autotrophic denitrification system suitable for low-temperature environment and having high-efficiency denitrification is started.

[0031] Optionally, the parameters of the influent water specifically include 60±5mg / L of NO3 - -N, 300±25mg / L of S2O3 2- -S.

[0032] Based on the successfully started sulfur autotrophic denitrification system, the present application further performs low-temperature domestication treatment, so that a denitrification system suitable for low-temperature environment and having high-efficiency denitrification can be obtained, which can still maintain high-efficiency denitrification efficiency in low-temperature environment (13-15℃).

[0033] The second technical scheme of the present application provides an application of the above low-temperature high-efficiency denitrification method in sewage treatment.

[0034] The third technical scheme of the present application provides a starting method of regulating and controlling an electron donor driven sulfur autotrophic denitrification system, and the steps include:

[0035] The seed sludge is inoculated into a biofilm reactor, the reactor maintains an anaerobic environment, and the starting of the sulfur autotrophic denitrification system which can be used for low-temperature high-efficiency denitrification is realized by regulating and controlling the types and concentrations of the electron donors and the domestication temperature;

[0036] The electron donor includes a carbon source and / or a sulfur source;

[0037] The starting step of the sulfur autotrophic denitrification system which can be used for low-temperature high-efficiency denitrification includes: first, utilizing the carbon source to perform heterotrophic denitrification domestication treatment, then utilizing the carbon source and the sulfur source to perform mixed denitrification domestication treatment, then utilizing the sulfur source to perform sulfur autotrophic denitrification domestication treatment, and finally performing low-temperature domestication to obtain a low-temperature high-efficiency denitrification system of the sulfur autotrophic denitrification system; the low temperature is 13-15℃.

[0038] Further, the anaerobic environment maintained by the reactor in the starting method has a dissolved oxygen concentration less than 0.02 mg / L, a hydraulic retention time (HRT) of 4±0.5 h, and an ambient temperature of 25-27°C.

[0039] Further, the carbon source includes at least one of sodium acetate, glucose, methanol, and sodium citrate.

[0040] Further, the sulfur source includes at least one of sodium thiosulfate, sulfide, and elemental sulfur.

[0041] Further, the step of the heterotrophic denitrification treatment includes: taking the carbon source as an electron donor, setting the influent parameters of the reactor to C / N=5 and S / N=0, and performing the heterotrophic denitrification treatment, and when the total nitrogen (TN) removal rate is stabilized at more than 97%, the heterotrophic denitrification treatment is completed.

[0042] When the total nitrogen (TN) removal rate is stabilized at more than 97%, it indicates that the heterotrophic denitrification system is successfully started.

[0043] Optionally, the influent parameters specifically include 60±5 mg / L of NO3 - -N and 300±25 mg / L of COD.

[0044] Further, the step of the mixed denitrification treatment includes: after the completion of the heterotrophic denitrification treatment, simultaneously taking the carbon source and the sulfur source as electron donors, setting the influent parameters of the reactor to C / N=1.67 and S / N=3.9, and performing the mixed denitrification treatment, and when the total nitrogen (TN) removal rate is stabilized at more than 98%, the mixed denitrification treatment is completed.

[0045] Optionally, the influent parameters specifically include 60±5 mg / L of NO3 - -N, 100±8 mg / L of COD, and 234±20 mg / L of S2O3 2- -S.

[0046] When the total nitrogen (TN) removal rate is stabilized at more than 98%, it indicates that the microbial community has gradually adapted to the environment with the sulfur source as an electron donor, and the system successfully transitions to the mixed denitrification stage.

[0047] Further, the step of the sulfur autotrophic denitrification treatment includes: after the completion of the mixed denitrification treatment, taking the sulfur source as an electron donor, setting the influent parameters of the reactor to C / N=0 and S / N=5, and performing the sulfur autotrophic denitrification treatment, and when the total nitrogen (TN) removal rate is stabilized at more than 94%, the sulfur autotrophic denitrification treatment is completed.

[0048] Optionally, the parameters of the influent water specifically include 60±5mg / L of NO3 - -N, 300±25mg / L of S2O3 2- -S.

[0049] When the total nitrogen (TN) removal rate is stabilized at more than 94%, it indicates that the sulfur autotrophic denitrification system is successfully started and has high-efficiency denitrification capacity.

[0050] Further, the low-temperature acclimation step includes:

[0051] The ambient temperature of the reactor is adjusted to 13-15 DEG C, the influent water parameters of the reactor are set as C / N=0 and S / N=5, when the total nitrogen removal rate is stabilized at more than 97%, the low-temperature acclimation is completed, and a sulfur autotrophic denitrification high-efficiency denitrification system suitable for a low-temperature environment is started.

[0052] Optionally, the parameters of the influent water specifically include 60±5mg / L of NO3 - -N, 300±25mg / L of S2O3 2- -S.

[0053] The present application discloses the following technical effects:

[0054] The present application realizes smooth transition from traditional heterotrophic denitrification to sulfur autotrophic denitrification by precisely regulating the type and concentration of the electron donor in stages, solves the problem of difficult start of the traditional sulfur autotrophic denitrification system, and after further acclimation treatment, obtains a denitrification high-efficiency denitrification system suitable for a low-temperature environment, which can still maintain high-efficiency denitrification performance in a low-temperature environment (13-15 DEG C), breaks through the limitation of traditional biological denitrification technology under low-temperature conditions, and provides an economic, environmentally-friendly and stable technical solution for the field of wastewater treatment.

[0055] The sulfur autotrophic denitrification provided by the present application does not need additional organic carbon source, reduces operation cost and carbon emission, reduces the dependence on chemical agents, has significant environmental benefits, optimizes the microbial community structure by precisely regulating the electron donor and reaction conditions, and the system impact resistance and stability are improved, so that it is more suitable for application in actual wastewater treatment engineering.

[0056] The present application is suitable for various nitrogen-containing wastewater treatment scenes, and has significant application value in wastewater treatment in low-temperature areas or low-temperature seasons, and provides a new technical approach for realizing efficient, economic and sustainable development of wastewater treatment. BRIEF DESCRIPTION OF DRAWINGS

[0057] The accompanying drawings, which constitute a part of this specification, are included to provide a further understanding of the application and of certain

[0058] Figure 1 The nitrogen removal effect of the start-up process of the electron donor-driven sulfur autotrophic denitrification system of Example 1 was regulated.

[0059] Figure 2 The nitrogen removal effect of the sulfur autotrophic denitrification system under low-temperature environment. DETAILED DESCRIPTION

[0060] Various exemplary embodiments of the present application will now be described in detail, with reference to the figures. The detailed description is made with reference to the accompanying drawings, in which:

[0061] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. In addition, for any numerical ranges recited herein, the endpoints are included in the ranges. Any intermediate value or any other value, whether or not included in the stated ranges, is also contemplated. The upper and lower limits of these smaller ranges can independently be included or excluded in the ranges.

[0062] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in further detail the methods and / or materials associated with the documents. In the case of conflict between the present specification and any document incorporated by reference, the present specification will control.

[0063] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0064] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0065] It should be noted that the present application does not describe in detail the conventional operation means in the art, and is not the focus of the present application.

[0066] The reactor used in the embodiment of the present application is a sequencing batch biofilm reactor (SBBR), the reactor volume is 5L, the filler is polyurethane sponge, the filler volume ratio is 20%, the reactor is always maintained in an anaerobic environment, the dissolved oxygen concentration is less than 0.02 mg / L, and the hydraulic retention time (HRT) is 4±0.5 hours.

[0067] The seed sludge used in the embodiment of the present application is derived from an aeration tank of a sewage treatment plant in Beijing.

[0068] The raw materials and reagents used in the embodiment of the present application are all commercially available products.

[0069] The carbon source used in the embodiment of the present application can be sodium acetate, glucose, methanol or sodium citrate, and sodium acetate is exemplarily described; the sulfur source used can be sodium thiosulfate, sulfide or elemental sulfur, and sodium thiosulfate is exemplarily described.

[0070] Example 1

[0071] The starting method of the electron donor-driven sulfur autotrophic denitrification system includes:

[0072] S1, seed sludge (MLSS is 3000±100 mg / L) is inoculated into a sequencing batch biofilm reactor, the reactor environmental temperature is set between 25-27℃, sodium acetate is used as a carbon source, the carbon-nitrogen ratio (C / N) of the influent is set to 5, and the specific influent indicators are: 60±5 mg / L of NO3 - -N, 300±25 mg / L of COD, and the total nitrogen (TN) removal rate is stably above 97%, indicating that the heterotrophic denitrification system is successfully started;

[0073] S2, sodium acetate is used as a carbon source, sodium thiosulfate is used as a sulfur source, the carbon-nitrogen ratio (C / N) of the influent is set to 1.67, the sulfur-nitrogen ratio (S / N) is set to 3.9, and the specific influent indicators are: 60±5 mg / L of NO3 - -N, 100±8 mg / L of COD and 234±20 mg / L of S2O3 2— -S, and the TN removal rate is stably above 98%, which successfully transitions to the mixed denitrification stage;

[0074] S3, the carbon source is completely removed, only the sulfur source (sodium thiosulfate) is used as an electron donor, the sulfur-nitrogen ratio (S / N) of the influent is set to 5, and the specific influent indicators are: 60 mg / L of NO3 - -N, 300 mg / L of S2O3 2- -S, and the TN removal rate is stably above 94%, which successfully starts the sulfur autotrophic denitrification system.

[0075] Figure 1The nitrogen removal effect of the start-up process of the electron donor driven sulfur autotrophic denitrification system of Example 1 is changed. As can be seen from the figure, in the 29 days of operation of the heterotrophic denitrification domestication treatment, the total nitrogen (TN) removal rate is stably above 97% for 29 days, indicating that the heterotrophic denitrification system is successfully started; in the 47 days of operation of the mixed denitrification domestication treatment (30-76 days in the figure), the TN removal rate is stably above 98% for 30 days from the 17th day (46th day in the figure) to the 47th day (76th day in the figure), and the microbial community has gradually adapted to the environment with sulfur as the electron donor, and the system has successfully transitioned to the mixed denitrification stage; in the 20 days of operation of the sulfur autotrophic denitrification domestication treatment (77-96 days in the figure), the TN removal rate is stably above 94% for 19 days from the 1st day (77th day in the figure) to the 20th day (96th day in the figure), and the sulfur autotrophic denitrification system is successfully started and has high nitrogen removal capacity.

[0076] Example 2

[0077] Low-temperature high-efficiency nitrogen removal step of sulfur autotrophic denitrification system:

[0078] Based on the sulfur autotrophic denitrification system started in Example 1, the environmental temperature of the reactor is adjusted to between 13-15℃, and the C / N of the influent is set to 0 and S / N to 5. The specific influent indicators are 60mg / L of NO3 - -N, 300mg / L of S2O3 2- -S, the TN removal rate is stably above 97%, achieving low-temperature high-efficiency nitrogen removal of the sulfur autotrophic denitrification system.

[0079] Figure 2 The nitrogen removal effect of the sulfur autotrophic denitrification system under low-temperature environment. As can be seen from the figure, in the 102 days of operation, the TN removal rate is stably above 97% for 62 days from the 40th day to the 102nd day, suitable for the successful start of the sulfur autotrophic denitrification high-efficiency nitrogen removal system under low-temperature environment, which still maintains high-efficiency nitrogen removal performance under low-temperature environment. Specifically: under the low-temperature condition of 13-15℃, the system runs for 102 days. Due to the sudden drop in air temperature, the TN removal rate fluctuates greatly in the first 50 days, and the TN removal rate on the 16th day is only 5.15%. On the 51st day, the TN removal rate of the system successfully recovered and stabilized above 97%, indicating that the sulfur autotrophic denitrification system can still maintain high-efficiency nitrogen removal performance under low-temperature environment, which is related to the stable start of the sulfur autotrophic denitrification system realized by regulating the electron donor in the early stage.

[0080] It can be seen from the contents of Examples 1 and 2 that the low-temperature high-efficiency denitrification method for regulating electron donor-driven sulfur autotrophic denitrification provided by the present application can effectively solve the problems of low denitrification efficiency, high operation cost and poor system stability of the existing biological denitrification technology in a low-temperature environment. The present application realizes the smooth transition from traditional heterotrophic denitrification to sulfur autotrophic denitrification by regulating the types and concentrations of electron donors in stages, and maintains high-efficiency denitrification performance under low-temperature conditions, thereby providing an economic, environmentally friendly and stable technical solution for the wastewater treatment field.

[0081] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be mutually referred to.

[0082] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A low-temperature and high-efficiency denitrification method for regulating electron donors to drive sulfur autotrophic denitrification, characterized in that the steps include: The seed sludge is inoculated into the biofilm reactor, which maintains an anaerobic environment. By regulating the type and concentration of electron donors and the acclimation temperature, the sulfur autotrophic denitrification system achieves low-temperature and high-efficiency denitrification. The reactor maintains an anaerobic environment with a dissolved oxygen concentration of less than 0.02 mg / L, a hydraulic retention time of 4 ± 0.5 h, and an ambient temperature of 25-27 °C; The electron donor includes a carbon source and / or a sulfur source; The step of realizing low-temperature and high-efficiency denitrification of the sulfur autotrophic denitrification system comprises: The ambient temperature of the reactor is set to 25-27°C, a carbon source is used as an electron donor, and the inlet parameters of the reactor are set to C / N=5, S / N=0, and heterotrophic denitrification acclimation treatment is carried out. When the total nitrogen removal rate is stable at more than 97%, the carbon source and the sulfur source are used as electron donors, and the inlet parameters of the reactor are set to C / N=1.67, S / N=3.9, and mixed denitrification acclimation treatment is carried out. When the total nitrogen removal rate is stable at more than 98%, the sulfur source is used as an electron donor, and the inlet parameters of the reactor are set to C / N=0, S / N=5, and sulfur autotrophic denitrification acclimation treatment is carried out. When the total nitrogen removal rate is stable at more than 94%, the ambient temperature of the reactor is adjusted to 13-15°C, and the inlet parameters of the reactor are set to C / N=0, S / N=5. When the total nitrogen removal rate is stable at more than 97%, a low-temperature and high-efficiency denitrification system of the sulfur autotrophic denitrification system is obtained. The low-temperature and high-efficiency denitrification system of the sulfur autotrophic denitrification system is used for denitrification treatment under low-temperature conditions; the low temperature is 13-15°C; The carbon source comprises at least one of sodium acetate, glucose, methanol and sodium citrate; The sulfur source includes at least one of sodium thiosulfate, sulfide and elemental sulfur.

2. Application of the low-temperature and high-efficiency denitrification method according to claim 1 in sewage treatment.

3. A method for starting a sulfur autotrophic denitrification system driven by regulating electron donors, characterized in that the steps include: The seed sludge is inoculated into the biofilm reactor, which maintains an anaerobic environment. By regulating the type and concentration of electron donors and the acclimation temperature, a sulfur autotrophic denitrification system capable of low-temperature and efficient nitrogen removal is started. The electron donor includes a carbon source and / or a sulfur source; The startup steps of the sulfur autotrophic denitrification system for low-temperature and high-efficiency denitrification include: firstly performing heterotrophic denitrification acclimation treatment using a carbon source, then performing mixed denitrification acclimation treatment using a carbon source and a sulfur source, then performing sulfur autotrophic denitrification acclimation treatment using a sulfur source, and finally performing low-temperature acclimation to obtain a low-temperature and high-efficiency denitrification system of the sulfur autotrophic denitrification system; The anaerobic environment in which the reactor is maintained in the startup method has a dissolved oxygen concentration of less than 0.02 mg / L, a hydraulic retention time of 4 ± 0.5 h, and an ambient temperature of 25-27°C; The carbon source includes at least one of sodium acetate, glucose, methanol and sodium citrate; the sulfur source includes at least one of sodium thiosulfate, sulfide and elemental sulfur; The heterotrophic denitrification acclimation treatment step includes: using a carbon source as an electron donor, setting the inlet parameters of the reactor to C / N=5, S / N=0, performing heterotrophic denitrification acclimation treatment, and completing the heterotrophic denitrification acclimation treatment when the total nitrogen removal rate is stabilized at more than 97%; The mixed denitrification acclimation treatment comprises: after the heterotrophic denitrification acclimation treatment is completed, using a carbon source and a sulfur source as electron donors, setting the inlet parameters of the reactor to C / N=1.67 and S / N=3.9, and performing the mixed denitrification acclimation treatment, and completing the mixed denitrification acclimation treatment when the total nitrogen removal rate is stabilized at more than 98%; The sulfur autotrophic denitrification acclimation treatment comprises: after the mixed denitrification acclimation treatment is completed, using a sulfur source as an electron donor, setting the inlet parameters of the reactor to C / N=0, S / N=5, and performing the sulfur autotrophic denitrification acclimation treatment, and completing the sulfur autotrophic denitrification acclimation treatment when the total nitrogen removal rate is stabilized at more than 94%; The low-temperature acclimation step includes: adjusting the ambient temperature of the reactor to 13-15° C., setting the water inlet parameters of the reactor to C / N=0, S / N=5, and completing the low-temperature acclimation when the total nitrogen removal rate is stabilized at above 97%.

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