Method for rapidly and stably starting autotrophic nitrification

Abstract

The invention relates to the technical field of environmental protection and sewage treatment, and discloses a method for rapidly and stably starting autotrophic nitrification. The method comprises the following steps: (1) pretreating nitrobacterium-containing sludge with the sludge concentration of 3-20g / L, and stopping when the sludge concentration is reduced by not more than 5% and / or the organic matter concentration is increased by not more than 5% to obtain pretreated sludge; and (2) contacting the pretreated sludge with sewage to be treated to start autotrophic nitrification to obtain effluent. The method provided by the invention not only can realize quick start and stable operation of autotrophic nitrification, but also can avoid the problems of intensified membrane pollution, poor settling performance, deteriorated effluent quality, complicated operation, difficult management and the like caused by high sludge concentration, and can effectively improve the nitrification performance of nitrifying bacteria of an autotrophic nitrification system; and a technical support can be provided for recycling of nitrogen elements in the sewage.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection and sewage treatment, and in particular relates to a method for quickly and stably starting autotrophic nitrification. Background Art

[0002] The traditional denitrification process of sewage treatment is based on the action of microorganisms. While removing organic pollutants, ammonia nitrogen (NH4 + -N) is oxidized to nitrate (NO3 - -N), and then reduced to nitrogen (N2) for removal. However, the essence of its technical principle is the removal of nitrogen, rather than resource recycling.

[0003] In order to utilize as many resources as possible in sewage, patent CN115557564A proposes a sustainable strategy for recovering nitrogen in the form of sodium nitrate from low-strength domestic sewage through ammonium ion exchange and regeneration, thereby reducing the emission of nitrogen-containing pollutants and alleviating nitrogen losses in the atmosphere.

[0004] However, in actual application, the above method still has problems such as slow growth and metabolism of autotrophic nitrifying bacteria, long generation cycle, poor stability and susceptibility to environmental influences. At the same time, compared with granular sludge, traditional nitrifying sludge has poor sedimentation and is prone to sludge swelling or sludge floating. In addition, due to the low sludge concentration, in order to increase the nitrification rate of the system, it is often necessary to increase the hydraulic retention time and require a larger sedimentation tank and reaction tank volume, which greatly increases the cost of biological denitrification and limits the application of autotrophic nitrifying bacteria.

[0005] Although inoculating with a higher concentration of nitrifying sludge can increase the number of nitrifying bacteria in the system, thereby accelerating the rate of conversion of ammonia nitrogen into nitrate and improving the overall nitrification efficiency, high-concentration sludge inoculation will lead to a series of operational and management challenges.

[0006] First, too high sludge concentration will cause the problem of difficulty in mud-water separation. For membrane bioreactors, it will lead to increased membrane fouling, membrane cleaning frequency, dissolved oxygen demand, and operational complexity. Secondly, high sludge concentration will also lead to decreased sludge settling performance and mud-water separation efficiency in secondary sedimentation tanks, increased pressure and dissolved oxygen demand in the sludge return system, sludge swelling, and deterioration of effluent water quality. Finally, due to the difficulty of microbial adaptability and possible mass transfer and mixing problems, the system needs a longer time to adjust and stabilize the microbial community before reaching a steady state, which makes the use of high sludge concentrations also have the dilemma of prolonged system startup time. In particular, the use of sludge with high sludge concentrations to directly carry out nitrification reactions in nitrogen recovery processes will lead to problems such as too long a start-up time for the reactor and increased membrane fouling.

[0007] Therefore, it is of great significance to provide a method that can simultaneously utilize the advantages of high sludge concentration and avoid the above-mentioned problems to achieve rapid start-up of autotrophic nitrification, and can also provide technical support for the resource utilization of nitrogen in sewage. Summary of the invention

[0008] The purpose of the present invention is to overcome the problems of aggravated membrane pollution, deteriorated effluent water quality and long start-up time in the prior art when using sludge with high sludge concentration for autotrophic nitrification.

[0009] In order to achieve the above object, the present invention provides a method for quickly and stably starting autotrophic nitrification, which comprises the following steps:

[0010] (1) pre-treating sludge containing nitrifying bacteria with a sludge concentration of 3-20 g / L, and stopping when the sludge concentration decreases by no more than 5% and / or the organic matter concentration increases by no more than 5%, thereby obtaining pre-treated sludge;

[0011] (2) contacting the pretreated sludge with the sewage to be treated to initiate autotrophic nitrification and obtain effluent;

[0012] The pretreatment conditions at least meet the following requirements: dissolved oxygen is not less than 2 mg / L, pH is 6.0-10.0, and temperature is 10-40°C;

[0013] The hydraulic retention time of the sewage to be treated is 6-100h.

[0014] Compared with the prior art, the method provided by the present invention has at least the following advantages:

[0015] (1) The method provided by the present invention can not only achieve rapid start-up and stable operation of autotrophic nitrification, but also avoid the problems of increased membrane pollution, poor sedimentation performance, deterioration of effluent quality, complex operation and difficult management caused by high sludge concentration, thus providing technical support for the resource utilization of nitrogen in sewage;

[0016] (2) Compared with other autotrophic nitrification start-up methods, the method provided by the present invention shortens the start-up time, improves the nitrification performance of the reaction tank, and can effectively reduce the floor space. The ability of nitrifying bacteria in the sludge pretreated by the method provided by the present invention to resist ammonia nitrogen shock load and salt stress is enhanced, and the activity is greatly improved compared with traditional nitrification sludge. While the HRT is short, the system effluent is still stable and meets the standards. Among them, the effluent ammonia nitrogen concentration is always lower than 0.1 mg / L, the ammonia removal rate can reach 99% or more, and the nitrification conversion rate is close to 100%;

[0017] (3) The method provided by the present invention does not require the addition of an additional organic carbon source, thereby reducing costs and the risk of secondary pollution. It can also overcome the problem of relatively poor settling properties of flocculent sludge, which easily causes a high concentration of suspended solids in the effluent of the secondary sedimentation tank, while maintaining the advantages of flocculent activated sludge, and at the same time has the advantages of both flocculent sludge and granular sludge. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a system used in the preferred method for rapidly and stably starting autotrophic nitrification of the present invention;

[0019] Figure 2 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Example 1 provided by the present invention;

[0020] Figure 3 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Example 2 provided by the present invention;

[0021] Figure 4 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Example 3 provided by the present invention;

[0022] Figure 5 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Comparative Example 1 provided by the present invention;

[0023] Figure 6 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Comparative Example 2 provided by the present invention;

[0024] Figure 7 A graph showing the relationship between membrane pollution in the reaction pool and time in Example 1 and Comparative Example 2 provided by the present invention;

[0025] Figure 8 A graph showing the relationship between the nitrite nitrogen concentration and the ammonia nitrogen removal rate over time in Comparative Example 3 provided by the present invention;

[0026] Fig. 9 This is a flow chart of the nitrogen recovery process in Application Example 1 provided by the present invention.

[0027] Description of reference numerals:

[0028] 1. Stirring device; 2. Aeration device;

[0029] 3. pH continuous automatic monitor; 4. pH, dissolved oxygen and temperature probes. DETAILED DESCRIPTION

[0030] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0031] As mentioned above, the present invention provides a method for quickly and stably starting autotrophic nitrification, which comprises the following steps:

[0032] (1) pre-treating sludge containing nitrifying bacteria with a sludge concentration of 3-20 g / L, and stopping when the sludge concentration decreases by no more than 5% and / or the organic matter concentration increases by no more than 5%, thereby obtaining pre-treated sludge;

[0033] (2) contacting the pretreated sludge with the sewage to be treated to initiate autotrophic nitrification and obtain effluent;

[0034] Wherein, the pretreatment conditions at least meet the following requirements: dissolved oxygen is not less than 2 mg / L, pH is 6.0-10.0, and temperature is 10-40°C;

[0035] The hydraulic retention time of the sewage to be treated is 6-100h.

[0036] Preferably, in step (2), the hydraulic retention time of the wastewater to be treated is 12-48 hours. Studies have found that under this preferred condition, the recovery of AOB and NOB activities can be accelerated by extending the hydraulic retention time.

[0037] Preferably, in step (1), the sludge concentration of the sludge containing nitrifying bacteria is 8-20 g / L.

[0038] Preferably, in step (1), the sludge containing nitrifying bacteria is at least one of excess sludge from a sewage treatment plant, anaerobic sludge, aerobic sludge, aerobic granular sludge, and nitrifying sludge.

[0039] Preferably, in step (1), alkali solution is added so that the molar ratio of the pretreated ammonium nitrogen to alkalinity is 1:0.5-3. Studies have found that in this preferred case, the pH of the reaction can be adjusted and maintained by the ratio of ammonium nitrogen to alkalinity.

[0040] More preferably, the alkali solution is at least one of an aqueous solution of calcium oxide, a sodium carbonate solution, a sodium bicarbonate solution, an aqueous solution of calcium hydroxide and a sodium hydroxide solution.

[0041] Preferably, the pretreated sludge is flocculent activated sludge.

[0042] According to a preferred embodiment, the MLVSS / MLSS of the pretreated sludge is 0.4-0.8, and the SVI is 80-150 mL / g.

[0043] Preferably, in step (1), during the pretreatment, ammonium salt is added to maintain the concentration of ammonium nitrogen at 20-200 mg / L. Studies have found that in this preferred case, the activity of nitrifying bacteria can be quickly restored by supplementing ammonium nitrogen.

[0044] Preferably, the ammonium salt is ammonium bicarbonate and / or ammonium chloride.

[0045] Preferably, in step (2), the sludge concentration during the start-up of the autotrophic nitrification is controlled to be 1-18 g / L.

[0046] Preferably, in step (2), the conditions for starting the autotrophic nitrification at least further satisfy: dissolved oxygen not less than 2 mg / L, pH 6.0-10.0, and temperature 10-40°C.

[0047] Preferably, in step (2), the initiation of the autotrophic nitrification is carried out under an autotrophic environment without the need for the additional addition of an organic carbon source.

[0048] Preferably, in step (2), the start-up time of the autotrophic nitrification is 7-25 days. It should be noted that the start-up time of the autotrophic nitrification is 7-25 days, which means that the start-up of the autotrophic nitrification is successfully achieved 7-25 days after the pre-treated sludge is contacted with the sewage to be treated.

[0049] Preferably, the pretreatment and the start-up of the autotrophic nitrification are both carried out in a reaction tank, and are both carried out under aeration and / or stirring conditions.

[0050] According to a preferred embodiment, in step (2), a solid-liquid separation device is added to the reaction tank to achieve control of sludge concentration during the start-up process of the autotrophic nitrification.

[0051] Further preferably, the solid-liquid separation device is a separation membrane.

[0052] It should be noted that, in the present invention, the separation membrane is a filter membrane commonly used in the art, and illustratively, it can be a hollow fiber membrane or a flat membrane.

[0053] According to another preferred embodiment, in step (2), the effluent from the reaction tank is introduced into a solid-liquid separation tank, and the sludge from the solid-liquid separation tank is returned to the reaction tank, so as to control the sludge concentration during the startup of the autotrophic nitrification.

[0054] Further preferably, the sludge return ratio of the solid-liquid separation tank is 25-100wt%.

[0055] More preferably, the solid-liquid separation tank is a sedimentation tank.

[0056] Preferably, the method of the present invention further comprises, in step (2), first introducing the wastewater to be treated into a pH adjustment tank to adjust the pH and then introducing it into the reaction tank to start the autotrophic nitrification.

[0057] Preferably, a pH probe is provided in the pH adjustment tank to monitor the pH during the adjustment process.

[0058] According to a preferred embodiment, the ammonia nitrogen concentration of the wastewater to be treated is 20-300 mg / L, and the salinity is 0-2 g / L Na + , pH is 6.0-10.0, and temperature is 10-40℃.

[0059] Preferably, during the pretreatment and / or the start-up of the autotrophic nitrification, pH, dissolved oxygen and temperature probes are arranged in the reaction tank to monitor the pH, dissolved oxygen and temperature of the system.

[0060] Preferably, in step (2), the ammonia nitrogen concentration of the effluent is not greater than 0.1 mg / L, the ammonia removal rate is not less than 99%, and the nitrification conversion rate is not less than 95%.

[0061] According to a preferred embodiment, after the startup of the autotrophic nitrification is completed, the conditions of the system during the stable operation of the autotrophic nitrification at least meet the following conditions: it is carried out under the condition of mud and water mixing, the dissolved oxygen is not less than 2 mg / L, the pH is 6.0-10.0, and the temperature is 10-40°C.

[0062] The following combination Figure 1 , provides a preferred method for quickly and stably starting autotrophic nitrification, comprising:

[0063] (1) Inoculating sludge containing nitrifying bacteria with a sludge concentration of 3-20 g / L into a reaction tank, turning on the aeration device 2 in the reaction tank for pretreatment, and at the same time, adding ammonium salt to the pretreatment tank every 5 hours to maintain the concentration of ammonium nitrogen, and adding alkali solution so that the molar ratio of ammonium nitrogen to alkalinity is 1:0.5-3, and stopping when the sludge concentration decreases by no more than 5% and / or the organic matter concentration increases by no more than 5%, thereby obtaining pretreated sludge;

[0064] (2) introducing the untreated sewage into the pH adjustment tank to adjust the pH and then introducing it into the reaction tank, turning on the aeration device 2 in the reaction tank, and starting the autotrophic nitrification with the pretreated sludge without adding any additional organic carbon source. At the same time, a solid-liquid separation device is added to the reaction tank to control the sludge concentration in the reaction tank to be 1-18 mg / L when the autotrophic nitrification is started, and finally obtaining effluent;

[0065] The pretreatment conditions at least meet the following requirements: dissolved oxygen is not less than 2 mg / L, pH is 6.0-10.0, and temperature is 10-40°C;

[0066] The hydraulic retention time of the sewage to be treated is 12-48h;

[0067] When adjusting the pH, the sewage is mixed by the stirring device 1, and the pH of the sewage is detected by the pH continuous automatic monitoring instrument 3;

[0068] During the pretreatment and the start-up of the autotrophic nitrification, the pH, dissolved oxygen and temperature in the reaction process are detected by the pH, dissolved oxygen and temperature probes 4 in the reaction tank.

[0069] The present invention is described in detail below by way of examples. Unless otherwise specified, the raw materials used are all common commercially available products.

[0070] Separation membrane: flat membrane;

[0071] Sludge containing nitrifying bacteria: It is flocculent sludge taken from the end of the aerobic tank of the sewage treatment plant, and the sludge concentration is 10g / L;

[0072] Wastewater to be treated: Wastewater prepared for the laboratory, with an ammonia nitrogen concentration of 100 mg / L and a salinity of 1.5 g / L Na + , pH 7.0-7.5, temperature 20-25°C;

[0073] Lye: Sodium bicarbonate solution.

[0074] Unless otherwise specified, "room temperature" in the following examples means a temperature of 20-25°C.

[0075] Unless otherwise specified, the following examples Figure 1 is performed in the system shown.

[0076] Example 1

[0077] This example is used to illustrate that the method for rapid and stable startup of autotrophic nitrification provided by the present invention is performed according to the following steps:

[0078] (1) At room temperature, nitrifying bacteria-containing sludge is inoculated into a reaction tank, and the aeration device 2 in the reaction tank is turned on for pretreatment. At the same time, ammonium bicarbonate is added to the pretreatment tank every 5 hours to maintain the concentration of ammonium nitrogen at 100 mg / L, and an alkali solution is added to make the molar ratio of ammonium nitrogen to alkalinity 1:2. When the sludge concentration decreases by no more than 5%, the pretreatment sludge is stopped to obtain a MLVSS / MLSS of 0.6 and a SVI of 120 mL / g;

[0079] (2) At room temperature, the wastewater to be treated is introduced into a pH adjustment tank to adjust the pH to 7.5 and then introduced into a reaction tank, the aeration device 2 in the reaction tank is turned on, and no additional organic carbon source is added to start the autotrophic nitrification with the pretreated sludge. At the same time, a flat membrane is inserted into the reaction tank to control the sludge concentration in the reaction tank to be 10 mg / L when the autotrophic nitrification is started, and finally an effluent with an ammonia nitrogen concentration of no more than 0.1 mg / L is obtained;

[0080] Among them, during the start-up process of autotrophic nitrification, the dissolved oxygen is not less than 3.0 mg / L and the pH is 7.5;

[0081] When adjusting the pH, the sewage is mixed by the stirring device 1, and the pH of the sewage is detected by the pH continuous automatic monitoring instrument 3;

[0082] During the pretreatment and autotrophic nitrification start-up process, the pH, dissolved oxygen and temperature in the reaction process are detected by the pH, dissolved oxygen and temperature probe 4 in the reaction tank;

[0083] The hydraulic retention time of the sewage to be treated in the reaction tank is 24h;

[0084] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 2 ,from Figure 2 It can be seen that on the 7th day, the ammonia removal rate was stable at more than 99%, the nitrification conversion rate was not less than 95%, and the nitrite nitrogen concentration was basically zero on the 7th day, indicating that the system achieved the successful start-up of autotrophic nitrification within 7 days and could operate stably in the later period.

[0085] Example 2

[0086] This embodiment is carried out in a similar manner to that of Embodiment 1, except that in step (2), the hydraulic retention time of the wastewater to be treated in the reaction tank is controlled to be 18 hours;

[0087] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 3 ,from Figure 3 It can be seen that the ammonia removal rate throughout the process is not less than 99%, and the nitrification conversion rate is not less than 95% on the 17th day, and the nitrite nitrogen concentration is basically zero on the 17th day, indicating that the system has achieved the successful start-up of autotrophic nitrification within 17 days and can operate stably in the later period.

[0088] Example 3

[0089] This example is carried out in a similar manner to Example 1, except that in the pretreatment of step (1), the concentration of ammonium nitrogen is maintained at 500 mg / L;

[0090] Finally, water is obtained;

[0091] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 4 ,from Figure 4 It can be seen that the ammonia removal rate reaches 90% on the 20th day, and the nitrification conversion rate is higher than 60% on the 30th day. The final ammonia nitrogen removal rate is not less than 99%, and the nitrification conversion rate is not less than 95%. The system has achieved the successful start-up of autotrophic nitrification within 45 days and can operate stably in the later period.

[0092] Comparative Example 1

[0093] This comparative example is carried out in a similar manner to Example 1, except that in step (2), the hydraulic retention time of the sewage to be treated in the aerobic reaction tank is controlled to be 4 hours; and finally effluent is obtained;

[0094] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 5 ,from Figure 5 It can be seen that on the 60th day, the ammonia removal rate was stable at more than 99%, and on the 100th day, the nitrification conversion rate was not less than 95%, indicating that the system took 100 days to successfully start autotrophic nitrification, and the startup time was too long.

[0095] Comparative Example 2

[0096] This comparative example is carried out in a similar manner to Example 1, except that the pretreatment operation in step (1) is not performed, specifically comprising:

[0097] At room temperature, the aeration device 2 in the reaction tank is turned on, and no additional organic carbon source is added. The sewage to be treated is first introduced into the pH adjustment tank to adjust the pH to 7.5, and then introduced into the reaction tank to directly contact with the sludge containing nitrifying bacteria to start autotrophic nitrification. At the same time, a flat membrane is inserted into the reaction tank to control the sludge concentration in the reaction tank to 10 mg / L, and finally effluent is obtained;

[0098] Among them, during the start-up process of autotrophic nitrification, the dissolved oxygen is not less than 3.0 mg / L and the pH is 7.5;

[0099] When adjusting the pH, the sewage is mixed by the stirring device 1, and the pH of the sewage is detected by the pH continuous automatic monitoring instrument 3;

[0100] During the autotrophic nitrification startup process, the pH, dissolved oxygen and temperature in the reaction process are detected by the pH, dissolved oxygen and temperature probe 4 in the reaction tank;

[0101] The hydraulic retention time of the sewage to be treated in the aerobic reaction tank is 24 hours;

[0102] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 6 ,from Figure 6 It can be seen that although the system successfully started autotrophic nitrification on the 12th day, the start-up time was longer than that in Example 1 (7 days).

[0103] also, Figure 7 The relationship between the TMP (transmembrane pressure difference) in the reaction tank of Example 1 (after pretreatment) and the comparative example (without pretreatment) and the time is shown. It can be seen that the membrane pollution in the comparative example is serious, which increases the complexity of the operation and the workload.

[0104] Comparative Example 3

[0105] This comparative example was carried out in a similar manner to Example 1, except that in step (1), the pretreatment conditions were 1.0 mg / L dissolved oxygen, 7.0 pH, and 20-25° C.

[0106] Finally, water is obtained;

[0107] The sampling interval is set to 24h, and the NH4 + -N, and NO2 in the effluent - -N, see the result Figure 8 ,from Figure 8 It can be seen that the ammonia removal rate was stabilized at more than 99% on the 60th day, and the nitrification conversion rate reached 95% on the 86th day, indicating that the system cannot quickly and effectively start autotrophic nitrification in a short time.

[0108] Application Example 1

[0109] This application example is used to illustrate that the method provided by the present invention can provide technical support for nitrogen recovery process. For specific process flow, refer to Fig. 9 And includes the following steps:

[0110] The system and method in Example 1 are applied to the nitrogen recovery process:

[0111] S1. At room temperature, inoculate the sludge containing nitrifying bacteria into the reaction tank, turn on the aeration device 2 in the reaction tank, and perform pretreatment. At the same time, add ammonium bicarbonate to the pretreatment tank every 5 hours to maintain the concentration of ammonium nitrogen at 100 mg / L, and add alkali solution so that the molar ratio of ammonium nitrogen to alkalinity is 1:2. Stop when the sludge concentration decreases by no more than 5%, and obtain pretreated sludge;

[0112] S2, the domestic sewage is first sent to the ammonia nitrogen separation and enrichment unit to capture ammonia nitrogen, and the effluent enters the subsequent mainstream deep treatment unit for treatment, and the salinity in the side stream regeneration tank is 2-10g Na + / L of concentrated liquid is introduced into an ammonia nitrogen separation and enrichment unit to elute and capture ammonia nitrogen to obtain high-salt and high-ammonia wastewater;

[0113] S3, introducing the high-salt and high-ammonia wastewater into the pH adjustment tank to adjust the pH to 7.5 and then introducing it into the reaction tank, turning on the aeration device 2 in the reaction tank, and starting the autotrophic nitrification with the pretreated sludge after solid-liquid separation without adding any additional organic carbon source, and at the same time, inserting a flat membrane into the reaction tank to control the sludge concentration in the reaction tank to be 10 mg / L when the autotrophic nitrification is started, and finally obtaining effluent;

[0114] S4. When the autotrophic nitrification is successfully started, the effluent is treated by denitrification or nitrogen recovery process, and a part of it enters the regeneration water tank for recycling as regeneration liquid, and the other part enters the deep concentration unit for subsequent treatment to obtain sodium nitrate product;

[0115] When adjusting the pH of high-salt and high-ammonia wastewater, the wastewater is mixed by a stirring device 1, and the pH of the wastewater is detected by a pH continuous automatic monitor 3;

[0116] Ultimately, the resource recovery of nitrogen in domestic sewage is achieved, and during the stable operation of the system's autotrophic nitrification, the dissolved oxygen in the reaction tank is not less than 2.0 mg / L, the pH is 6.0-10.0, and the temperature is 10-40°C.

[0117] It can be seen from the above results that the method provided by the present invention can not only achieve rapid start-up and stable operation of autotrophic nitrification, but also avoid the problems of aggravated membrane pollution caused by high sludge concentration, poor sedimentation performance, deterioration of effluent water quality, complex operation and difficult management, etc. It can effectively improve the nitrification performance of nitrifying bacteria in the autotrophic nitrification system, and can also provide technical support for the resource utilization of nitrogen in sewage.

[0118] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for rapidly and stably starting autotrophic nitrification, characterized in that: The method comprises the following steps: (1) pre-treating sludge containing nitrifying bacteria with a sludge concentration of 3-20 g / L, and stopping when the sludge concentration decreases by no more than 5% and / or the organic matter concentration increases by no more than 5%, thereby obtaining pre-treated sludge; (2) contacting the pretreated sludge with the sewage to be treated to initiate autotrophic nitrification and obtain effluent; Wherein, the pretreatment conditions at least meet the following requirements: dissolved oxygen is not less than 2 mg / L, pH is 6.0-10.0, and temperature is 10-40°C; The hydraulic retention time of the sewage to be treated is 6-100h.

2. The method according to claim 1, characterized in that In step (1), during the pretreatment, ammonium salt is added to maintain the concentration of ammonium nitrogen at 20-200 mg / L.

3. The method according to claim 1 or 2, characterized in that: In step (2), the sludge concentration during the start-up of the autotrophic nitrification is controlled to be 1-18 g / L.

4. The method according to claim 1 or 2, characterized in that: In step (2), the conditions for starting the autotrophic nitrification at least meet the following requirements: dissolved oxygen is not less than 2 mg / L, pH is 6.0-10.0, and temperature is 10-40°C.

5. The method according to claim 1 or 2, characterized in that: In step (2), the start-up time of the autotrophic nitrification is 7-25 days.

6. The method according to claim 1 or 2, characterized in that: The pretreatment and the start-up of the autotrophic nitrification are both carried out in a reaction tank and are both carried out under aeration and / or stirring conditions.

7. The method according to claim 6, characterized in that The method further comprises, in step (2), first introducing the wastewater to be treated into a pH adjustment tank to adjust the pH and then introducing the wastewater into the reaction tank to start the autotrophic nitrification.

8. The method according to claim 6 or 7, characterized in that: During the pretreatment and / or the start-up of the autotrophic nitrification, pH, dissolved oxygen and temperature probes are arranged in the reaction tank to monitor the pH, dissolved oxygen and temperature of the system.

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