A combined process wastewater treatment system and method

Abstract

The application discloses a combined process wastewater treatment system and method, which comprises an anaerobic ammonia oxidation bypass system and a main flow treatment system, effluent of the anaerobic ammonia oxidation bypass system flows into the main flow treatment system, and the main flow treatment system is provided with nitrous nitrogen NO2 ‑ -N, sludge of the anaerobic ammonia oxidation bypass system is discharged into the main flow treatment system at the beginning of an operation stage of the combined process wastewater treatment system, the main flow treatment system is provided with anaerobic ammonia oxidation bacteria AAOB, an anaerobic ammonia oxidation denitrification process is started in the main flow treatment system, and a combined denitrification process is formed with an original denitrification process of the main flow treatment system. The technical scheme realizes combined denitrification of a short-cut nitrification process, an anaerobic ammonia oxidation process and a nitrification-denitrification process in a wastewater treatment process, improves total nitrogen TN removal capacity of the wastewater treatment, saves energy consumption and an additional carbon source, total nitrogen TN of the wastewater treatment stably reaches a standard, and stable operation of a domestic wastewater treatment system is realized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of new biological denitrification, and relates to a combined process wastewater treatment system and method. BACKGROUND

[0002] The generation of urban domestic sewage is closely related to people's life. If not properly treated, it will directly affect the ecological construction of the city and the living environment of the people. 2 The / O (Anaerobic-Anoxic-Oxic) process is a commonly used process for treating urban domestic sewage, and mainly removes total nitrogen TN through traditional denitrification technology (nitrification-denitrification). However, it has some disadvantages, such as difficulty in meeting the total nitrogen TN standard, high operation energy consumption, and the need for additional carbon source. Anaerobic ammonia oxidation technology is increasingly mature and is widely used in the biological treatment of high-nitrogen wastewater such as industrial wastewater, landfill leachate, and sludge digestion liquid. According to statistics, there are more than 110 production anaerobic ammonia oxidation projects in the world, but most of them are used for side stream treatment of municipal sewage. The introduction of anaerobic ammonia oxidation technology into the mainstream process of municipal sewage can significantly reduce the amount of additional carbon source, thereby effectively reducing the operation cost of wastewater denitrification. Due to the differences in water quality, water temperature, and water quantity between domestic sewage and high-nitrogen wastewater such as industrial wastewater, landfill leachate, and sludge digestion liquid, anaerobic ammonia oxidation technology faces many technical bottlenecks in the application of mainstream wastewater treatment processes. Anaerobic ammonia oxidation technology is a new type of biological denitrification technology, and its principle is as follows:

[0003]

[0004] The required nitrite NO2 - -N can be provided by short-cut nitrification:

[0005]

[0006] Compared with traditional nitrification-denitrification, anaerobic ammonia oxidation has the advantages of saving aeration energy consumption, not needing additional carbon source, and less sludge production. In the field of high-ammonia-nitrogen wastewater treatment, such as sludge digestion liquid, landfill leachate, and livestock and poultry breeding wastewater, mainstream anaerobic ammonia oxidation has been achieved. However, there are few reports on the application of anaerobic ammonia oxidation in domestic sewage treatment, especially in the mainstream anaerobic ammonia oxidation of domestic sewage. At present, most of the existing technologies are still in the laboratory pilot study stage. The mainstream anaerobic ammonia oxidation process for domestic sewage in the prior art has the following problems: (1) the generation period of anaerobic ammonia oxidation bacteria (AAOB) is long (usually 11 days), the strain yield is low, and it is difficult to enrich. The activity and abundance of anaerobic ammonia oxidation bacteria in the wastewater treatment system are low; (2) in the mainstream treatment system of domestic sewage, anaerobic ammonia oxidation bacteria (AAOB) face double substrate competition. In the nitrification stage of the aerobic stage, anaerobic ammonia oxidation bacteria (AAOB) need to compete with nitrite-oxidizing bacteria (nitrifying bacteria, NOB) for nitrite NO2- - N substrate; in the anaerobic or anoxic denitrification stage, anaerobic ammonia oxidation bacteria (AAOB) need to compete with denitrifying bacteria for nitrite nitrogen NO2 - - N substrate. How to achieve the rapid start-up and long-term stable operation of the anaerobic ammonia oxidation of domestic sewage with low carbon-nitrogen ratio (C / N) is still a recognized problem. SUMMARY

[0007] The technical solution aims to overcome the defects of current domestic sewage treatment, and provides a combined process system and method for domestic sewage treatment, which realizes the combined denitrification of nitrification-denitrification process, shortcut nitrification and anaerobic ammonia oxidation process in the domestic sewage treatment process, improves the total nitrogen (TN) removal capacity of the domestic sewage treatment system, and realizes the stable operation of the domestic sewage treatment system.

[0008] The technical solution is as follows:

[0009] A combined process wastewater treatment system, characterized in that: the combined process treatment system comprises an anaerobic ammonia oxidation bypass system and a mainstream treatment system, the anaerobic ammonia oxidation bypass system comprises a plurality of connected reaction tanks, the reaction tanks of the anaerobic ammonia oxidation bypass system are each provided with a water inlet and a water outlet, the mainstream treatment system comprises a plurality of sequentially connected reaction tanks, the reaction tanks of the mainstream treatment system are each provided with a water inlet and a water outlet, the anaerobic ammonia oxidation bypass system is connected with the mainstream treatment system through a water port connection and a sludge port connection, the number of reaction tanks of the mainstream treatment system into which the effluent of the anaerobic ammonia oxidation bypass system flows is one or more than one, the effluent of the anaerobic ammonia oxidation bypass system flows into the mainstream treatment system, and the mainstream treatment system is provided with nitrite nitrogen NO2 - -N, the number of reaction tanks of the mainstream treatment system into which the sludge of the anaerobic ammonia oxidation bypass system is discharged is one or more than one, the sludge of the anaerobic ammonia oxidation bypass system is discharged into the mainstream treatment system at the beginning of the operation stage of the combined process wastewater treatment system, the mainstream treatment system is provided with anaerobic ammonia oxidation bacteria (AAOB), the anaerobic ammonia oxidation denitrification process is started in the mainstream treatment system, and a combined denitrification process is formed with the original denitrification process of the mainstream treatment system.

[0010] The process method of the combined process wastewater treatment system as described above comprises a start-up stage and an operation stage:

[0011] a) In the start-up stage: the anaerobic ammonia oxidation bypass system generates nitrite nitrogen NO2 - -N through shortcut nitrification reaction and cultivates anaerobic ammonia oxidation (AAOB) bacteria, and the nitrite nitrogen NO2 -When the -N generation rate is > 10 mg / L·h and the anaerobic ammonia oxidation AAOB bacteria MLSS of the anaerobic ammonia oxidation bypass system is > 1500 mg / L, the combined process sewage treatment system is started up completely;

[0012] b) In the running stage, the anaerobic ammonia oxidation bypass system transports the anaerobic ammonia oxidation AAOB bacteria cultivated in the above-mentioned a) start-up stage to the mainstream treatment system connected thereto through sludge discharge, so that the anaerobic ammonia oxidation denitrification process is started up in the mainstream treatment system, and a combined denitrification process is formed with the original denitrification process of the mainstream treatment system.

[0013] Further, the reaction tank of the anaerobic ammonia oxidation bypass system comprises a bypass short-cut nitrification tank I and a bypass anaerobic ammonia oxidation tank, part of the effluent of the bypass short-cut nitrification tank I flows into the reaction tank of the mainstream treatment system, another part of the effluent of the bypass short-cut nitrification tank I flows into the bypass anaerobic ammonia oxidation tank, the effluent of the bypass anaerobic ammonia oxidation tank flows into the reaction tank of the mainstream treatment system, and the sludge of the bypass anaerobic ammonia oxidation tank is discharged into the reaction tank of the mainstream treatment system at the beginning of the running stage of the combined process sewage treatment system.

[0014] Further, the above-mentioned anaerobic ammonia oxidation bypass system further comprises a bypass short-cut nitrification tank II, part of the effluent of the bypass short-cut nitrification tank I flows into the bypass short-cut nitrification tank II, another part of the effluent of the bypass short-cut nitrification tank I flows into the bypass anaerobic ammonia oxidation tank, the effluent of the bypass short-cut nitrification tank II flows into the reaction tank of the mainstream treatment system, the effluent of the bypass anaerobic ammonia oxidation tank flows into the reaction tank of the mainstream treatment system, and the sludge of the bypass anaerobic ammonia oxidation tank is discharged into the reaction tank of the mainstream treatment system at the beginning of the running stage of the combined process sewage treatment system.

[0015] Further, the reaction tank of the mainstream treatment system comprises an anaerobic tank, an anoxic tank, an aerobic tank and a secondary sedimentation tank connected in sequence, the effluent of the anaerobic tank flows into the anoxic tank, the effluent of the anoxic tank flows into the aerobic tank, the effluent of the aerobic tank flows into the secondary sedimentation tank, part of the sludge-water mixture of the aerobic tank is refluxed to the anoxic tank, the sludge of the secondary sedimentation tank is refluxed to the anaerobic tank, the effluent of the bypass short-cut nitrification tank I or the bypass short-cut nitrification tank II in the anaerobic ammonia oxidation bypass system, and the effluent of the bypass anaerobic ammonia oxidation tank all flow into the anaerobic tank of the mainstream treatment system, and the sludge of the bypass anaerobic ammonia oxidation tank is discharged into the anaerobic tank or simultaneously discharged into the anaerobic tank and the anoxic tank at the beginning of the running stage of the combined process sewage treatment system.

[0016] Further, the main stream treatment system further comprises a low-oxygen aeration tank arranged between the anoxic tank and the aerobic tank, the effluent of the anoxic tank flows into the low-oxygen aeration tank, the effluent of the low-oxygen aeration tank flows into the aerobic tank, part of the sludge-water mixture in the low-oxygen aeration tank flows back to the anoxic tank, the effluent of the short-cut nitrification tank I or the short-cut nitrification tank II in the anammox bypass system, and the effluent of the anammox tank all flow into the anoxic tank of the main stream treatment system, the sludge in the anammox tank is discharged into the anoxic tank at the beginning of the operation of the combined process wastewater treatment system, or is simultaneously discharged into the anoxic tank and the anoxic tank.

[0017] The anammox bypass system comprising the short-cut nitrification tank I and the anammox tank comprises the following process steps during the a) start-up phase:

[0018] a) Inoculation of the short-cut nitrification tank I and the anammox tank: inoculate the short-cut nitrification tank I with AOB sludge, the inoculation amount of MLSS is about 1500-3500 mg / L, inoculate the anammox tank with AAOB sludge, the inoculation amount of MLSS is greater than 100 mg / L;

[0019] b) Short-cut nitrification reaction in the short-cut nitrification tank I: the wastewater to be treated in the main stream treatment system enters the short-cut nitrification tank I, after the water inlet is completed, according to the content of NH4 + -N in the wastewater, supplement the short-cut nitrification tank I with a compound containing NH4 + -N, turn on the air blower for aeration, control the dissolved oxygen DO to be less than or equal to 1.5 mg / L, and perform a short-cut nitrification reaction to convert all NH4 + -N into NO2 - -N, when the volume of NH4 + -N in the short-cut nitrification tank I is less than 1 mg / L, the reaction is completed, and the effluent is obtained by standing and sedimentation, the total effluent volume is 30-60% of the volume, and after the effluent is completed, the next reaction cycle is waited for;

[0020] c) Anammox reaction in the anammox tank: part of the effluent of the short-cut nitrification tank I enters the anammox tank, and part of the effluent enters the anoxic tank of the main stream treatment system, according to the total nitrogen TN removal load of the anammox AAOB bacteria, supplement the anammox tank with a compound containing NH4 + -N, so that the volume of NH4 + -N in the anammox tank is about 1:1.32; when the volume of NH4 - -N in the anammox tank is less than 1 mg / L, the reaction is completed, and the effluent is obtained by standing and sedimentation, the total effluent volume is 30-60% of the volume, and after the effluent is completed, the next reaction cycle is waited for; +- N < 10 mg / L, the reaction is over, standing, precipitation, effluent to the main stream treatment system of anaerobic tank, the effluent volume is 30-60% of the volume, and after the completion of the effluent, it waits to enter the next reaction cycle;

[0021] The sludge of the by-pass anaerobic ammonia oxidation tank is not discharged into the main stream treatment system, and when the nitrite nitrogen NO2 - - N generation rate > 10 mg / L·h, and AAOB bacteria MLSS in the by-pass anaerobic ammonia oxidation tank > 1500 mg / L, the combined process sewage treatment system is started and completed.

[0022] The anaerobic ammonia oxidation by-pass system including the by-pass short-cut nitrification tank I, the by-pass short-cut nitrification tank II and the by-pass anaerobic ammonia oxidation tank in the a) starting stage includes the following process steps:

[0023] a) By-pass short-cut nitrification tank I, by-pass short-cut nitrification tank II and by-pass anaerobic ammonia oxidation tank inoculation: take short-cut nitrification bacteria AOB seed sludge and respectively pour into the by-pass short-cut nitrification tank I and the by-pass short-cut nitrification tank II, the inoculum amount of bacteria MLSS is approximately 1500-3500 mg / L, take anaerobic ammonia oxidation bacteria seed AAOB seed sludge and pour into the by-pass anaerobic ammonia oxidation tank, the inoculum amount of bacteria MLSS is > 100 mg / L;

[0024] b) Short-cut nitrification reaction in the by-pass short-cut nitrification tank I: take the high ammonia nitrogen wastewater after decarburization pretreatment as the by-pass short-cut nitrification tank I influent to start the by-pass system, the dissolved oxygen DO is ≤ 1.5 mg / L; the influent is stirred at the same time, after the influent is over, the air blower is opened to aerate, the short-cut nitrification reaction is carried out, part of the ammonia nitrogen NH4 + - N is converted into nitrite nitrogen NO2 - - N, the effluent ammonia nitrogen NH4 + - N: nitrite nitrogen NO2 - - N = 1:1~1:1.3, after the aeration is over, standing, precipitation, respectively, effluent to the by-pass short-cut nitrification tank II and the by-pass anaerobic ammonia oxidation tank, the total effluent volume is 30-60% of the volume, and after the completion of the effluent, it enters the next reaction cycle;

[0025] c) A part of the by-pass short-cut nitrification tank I effluent flows into the by-pass anaerobic ammonia oxidation tank to carry out the anaerobic ammonia oxidation reaction, the stirring makes the anaerobic ammonia oxidation reaction sufficient, when the ammonia nitrogen NH4 + - N < 10 mg / L, the reaction is over, standing, precipitation, effluent to the main stream treatment system of anaerobic tank, the effluent volume is 30-60% of the volume, and after the completion of the effluent, it waits to enter the next reaction cycle;

[0026] d) Another part of the effluent of the bypass short-cut nitrification tank I flows into the bypass short-cut nitrification tank II to perform a short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + -N is all converted into nitrite nitrogen NO2 - -N, after the reaction, standing, precipitation, effluent to the reaction tank of the main stream sewage treatment system, the effluent volume is 30-60% of the volume, and after the effluent is completed, waiting for entering the next reaction period;

[0027] When the generation rate of nitrite nitrogen NO2 - -N is greater than 10 mg / L·h, and the AAOB bacteria MLSS in the anaerobic ammonia oxidation tank is greater than 1500 mg / L, the combined process sewage treatment system is started and completed.

[0028] The main stream treatment system comprising the anaerobic tank, the anoxic tank, the aerobic tank and the secondary sedimentation tank in sequence in the a) starting stage, the sludge of the bypass anaerobic ammonia oxidation tank is not discharged into the main stream treatment system, and the main stream treatment system performs denitrification in a nitrification-denitrification manner, comprising the following process steps:

[0029] a) The mixed sewage formed by the effluent of the bypass short-cut nitrification tank I or the bypass short-cut nitrification tank II of the anaerobic ammonia oxidation bypass system and the bypass anaerobic ammonia oxidation tank enters the anaerobic tank of the main stream treatment system, and the dissolved oxygen DO in the anaerobic tank is controlled to be less than 0.2 mg / L, so that the denitrification reaction is performed in the anaerobic tank;

[0030] b) The mixed sewage after the denitrification reaction in the anaerobic tank of step a) enters the anoxic tank, and the dissolved oxygen DO in the anoxic tank is controlled to be less than 0.3 mg / L, so that the denitrification reaction is performed in the anoxic tank;

[0031] c) The mixed sewage after the denitrification reaction in the anoxic tank of step b) enters the aerobic tank, and the dissolved oxygen DO in the aerobic tank is controlled to be 1-5 mg / L, so that the nitrification reaction is performed in the aerobic tank, and the nitrifying bacteria (NOB) oxidize the ammonia nitrogen NH4 + -N into nitrate nitrogen NO3 - -N, and the ammonia nitrogen NH4 + -N is removed; the generated nitrate nitrogen NO3 - -N is removed by the denitrification of the sludge-water mixture refluxed to the anoxic tank, and the sludge-water mixture reflux ratio is 50-300%;

[0032] d) The sludge-water mixture after the nitrification reaction in the aerobic tank of step c) enters the secondary sedimentation tank to separate the sludge and the water, the clear liquid flows out of the main stream treatment system, and the sludge is refluxed to the anaerobic tank, and the reflux ratio is 30%-100%;

[0033] The main stream treatment system comprising the anaerobic tank, the anoxic tank, the low-oxygen aeration tank, the aerobic tank and the secondary sedimentation tank connected in sequence, in the a) starting stage, the sludge of the by-pass anaerobic ammonia oxidation tank is not discharged into the main stream treatment system, and the main stream treatment system carries out denitrification in the nitration-denitrification and short-cut nitrification mode, comprising the following process steps:

[0034] a) The mixed sewage formed by the sewage to be treated, the by-pass short-cut nitrification tank I of the by-pass anaerobic ammonia oxidation system and the effluent of the by-pass anaerobic ammonia oxidation tank is introduced into the anaerobic tank of the main stream treatment system, the dissolved oxygen DO of the anaerobic tank is controlled to be less than 0.2 mg / L, and the denitrification reaction is carried out in the anaerobic tank;

[0035] b) The mixed sewage after the denitrification reaction of the anaerobic tank in step a) is introduced into the anoxic tank, the dissolved oxygen DO of the anoxic tank is controlled to be less than 0.3 mg / L, and the denitrification reaction is carried out in the anoxic tank;

[0036] c) The sewage after the reaction of the anoxic tank in step b) is introduced into the low-oxygen aeration tank, the dissolved oxygen DO in the low-oxygen aeration tank is controlled to be 0.1-0.5 mg / L, the short-cut nitrification reaction and the denitrification reaction are simultaneously carried out in the low-oxygen aeration tank, the short-cut nitrification bacteria (AOB) oxidize the ammonia nitrogen NH4 + -N to nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N is removed, the generated nitrite nitrogen NO2 - -N is denitrified to nitrogen N2, the total nitrogen TN is removed, and the sludge-water mixture in the low-oxygen aeration tank is backflowed to the anoxic tank, and the backflow ratio is 30%-100%;

[0037] d) The mixed sewage after the reaction of the low-oxygen aeration tank in step c) is introduced into the aerobic tank, the dissolved oxygen DO in the aerobic tank is controlled to be 1-5 mg / L, the nitrification reaction is carried out in the aerobic tank, the nitrification bacteria (NOB) oxidize the ammonia nitrogen NH4 + -N to nitrate nitrogen NO3 - -N, the ammonia nitrogen NH4 + -N is removed; the generated nitrate nitrogen NO3 - -N is backflowed to the anoxic tank with the sludge-water mixture for denitrification removal, and the sludge-water mixture backflow ratio is 50-200%;

[0038] e) The sludge-water mixture after the nitrification reaction of the aerobic tank in step d) is introduced into the secondary sedimentation tank for sludge-water separation, the clear liquid is self-flowed out of the main stream treatment system, and the sludge is backflowed to the anaerobic tank, and the backflow ratio is 30%-100%;

[0039] Further, the by-pass anaerobic ammonia oxidation system comprising the by-pass short-cut nitrification tank I and the by-pass anaerobic ammonia oxidation tank, in the b) running stage, comprises the following process steps:

[0040] In the running stage, the anammox bacteria cultivated in the starting stage of the anammox bypass system are discharged into the anaerobic tank of the main stream treatment system with the sludge of the anammox bypass tank, and in the main stream treatment system, the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexisting process of nitrification-denitrification and anammox, and the nitrification-denitrification and anammox process is combined to run for denitrification;

[0041] In the running stage, the anammox bypass system comprises the following process steps:

[0042] a) short-cut nitrification reaction in the bypass short-cut nitrification tank I: the wastewater to be treated enters the bypass short-cut nitrification tank I, and according to the ammonia nitrogen content in the wastewater, an ammonia nitrogen NH4 + -N compound is supplemented into the bypass short-cut nitrification tank I, and after the water inlet is completed, aeration is performed to control the dissolved oxygen DO≤1.5 mg / L, and the short-cut nitrification reaction is performed; the short-cut nitrification converts all the ammonia nitrogen NH4 + -N into nitrite nitrogen NO2 - -N; after the reaction is completed, standing, sedimentation and water outlet are performed, and the water outlet flows into the anammox bypass tank and the reaction tank of the main stream treatment system respectively, and the total water outlet amount is 30-60% of the volume, and after the water outlet is completed, the next reaction period is waited for;

[0043] b) anammox reaction in the bypass anammox tank: part of the water outlet of the bypass short-cut nitrification tank I flows into the bypass anammox tank, and according to the total nitrogen TN removal load of the anammox bacteria AAOB, an appropriate amount of ammonia nitrogen NH4 + -N compound is added into the bypass anammox tank, so that the ammonia nitrogen NH4 + -N in the volume is: nitrite nitrogen NO2 - -N≈1:1.32; stirring is performed to fully perform the anammox reaction; after the reaction is completed, standing, sedimentation and water outlet are performed to the reaction tank of the main stream treatment system, and the water outlet amount is 30-60% of the volume, and after the water outlet is completed, the next reaction period is waited for;

[0044] c) sludge discharge of the bypass anammox tank into the main stream treatment system: the anammox bacteria AAOB cultivated in the starting stage of the anammox bypass system are discharged into the anaerobic tank of the main stream treatment system with the sludge of the bypass anammox tank, and in the main stream treatment system, the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexisting process of nitrification-denitrification and anammox, and the nitrification-denitrification and anammox process is combined to run for denitrification.

[0045] Further, the anammox bypass system comprising the bypass short-cut nitrification tank I, the bypass short-cut nitrification tank II and the bypass anammox tank comprises the following process steps in the running stage of the b):

[0046] a) High ammonia nitrogen wastewater enters the bypass short-cut nitrification tank I for short-cut nitrification reaction, and ammonia nitrogen NH4 + -N is partially converted into nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N in the effluent is controlled to be less than 10 mg / L, and the reaction is ended. - -N=1:1~1:1.3, the reaction is ended, and the effluent is respectively discharged to the bypass anaerobic ammonia oxidation tank and the bypass short-cut nitrification tank II, and the total effluent volume is 30-60% of the volume.

[0047] b) A part of the effluent from the bypass short-cut nitrification tank I flows into the bypass anaerobic ammonia oxidation tank for anaerobic ammonia oxidation reaction, and the anaerobic ammonia oxidation reaction is fully stirred, and when the ammonia nitrogen NH4 + -N in the bypass anaerobic ammonia oxidation tank is less than 10 mg / L, the reaction is ended, and the effluent is discharged to the reaction tank of the main stream treatment system, and the effluent volume is 30-60% of the volume.

[0048] c) Another part of the effluent from the bypass short-cut nitrification tank I flows into the bypass short-cut nitrification tank II for short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + -N is completely converted into nitrite nitrogen NO2 - -N, and the reaction is ended.

[0049] Further, in the b) operation stage, the anammox AAOB bacteria cultivated in the start-up stage of the anaerobic ammonia oxidation bypass system are discharged into the anaerobic tank of the main stream treatment system with the sludge of the bypass anaerobic ammonia oxidation tank, and in the main stream treatment system, the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexisting process of nitrification-denitrification and anaerobic ammonia oxidation, and the nitrification-denitrification and anaerobic ammonia oxidation process is combined to operate for denitrification, and the process steps include the following:

[0050] a) The mixed wastewater formed by the effluent from the bypass short-cut nitrification tank I or the bypass short-cut nitrification tank II and the bypass anaerobic ammonia oxidation tank of the anaerobic ammonia oxidation bypass system enters the anaerobic tank of the main stream treatment system, the sludge of the bypass anaerobic ammonia oxidation tank is discharged into the anaerobic tank of the main stream treatment system, and the nitrite nitrogen NO2 -- N and anaerobic ammonia oxidation bacteria AAOB bacteria from the sludge of the by-pass anaerobic ammonia oxidation tank exist in the anaerobic tank simultaneously, the dissolved oxygen DO of the anaerobic tank is controlled to be less than 0.2 mg / L, so that the anaerobic ammonia oxidation reaction and the denitrification reaction are simultaneously carried out in the anaerobic tank, the anaerobic ammonia oxidation AAOB bacteria compete with the denitrification bacteria for the substrate, and nitrite nitrogen NO2 - - N, the ammonia nitrogen NH4 in the sewage is reused + - N, the anaerobic ammonia oxidation reaction is carried out, and total nitrogen TN is removed

[0051] b) After the reaction of the anaerobic tank, the sludge-water mixture enters the anoxic tank, the dissolved oxygen DO of the anoxic tank is controlled to be less than 0.3 mg / L, the anaerobic ammonia oxidation AAOB bacteria compete with the denitrification bacteria for the substrate, and nitrite nitrogen NO2 - - N, the ammonia nitrogen NH4 in the sewage is reused + - N, the anaerobic ammonia oxidation reaction is carried out, and total nitrogen TN is removed

[0052] c) After the reaction of the anoxic tank, the sludge-water mixture enters the aerobic tank, the dissolved oxygen DO in the aerobic tank is controlled to be 1-5 mg / L, so that the nitrification reaction occurs in the aerobic tank, the nitrification bacteria (NOB) oxidize the residual ammonia nitrogen NH4 + - N into nitrate nitrogen NO3 - - N, the ammonia nitrogen NH4 is removed + - N, the generated nitrate nitrogen NO3 - - N is returned to the anoxic tank (12) with the sludge-water mixture to be removed in the anaerobic ammonia oxidation mode and the denitrification mode. The sludge-water mixture return ratio is 50-300%.

[0053] d) After the reaction of the aerobic tank, the sludge-water enters the secondary sedimentation tank for sludge-water separation, the clear liquid flows out of the main stream system, and the sludge is returned to the anaerobic tank with a return ratio of 30%-100%.

[0054] Further, in the b) operation stage, the anaerobic ammonia oxidation AAOB bacteria cultivated in the start-up stage of the anaerobic ammonia oxidation by-pass system are discharged into the anaerobic tank of the main stream treatment system with the sludge of the by-pass anaerobic ammonia oxidation tank, in the main stream treatment system, the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexistence process of nitrification-denitrification, short-cut nitrification and anaerobic ammonia oxidation, the nitrification-denitrification, short-cut nitrification and anaerobic ammonia oxidation processes are combined to operate for denitrification, and the process steps include the following:

[0055] a) The mixed sewage to be treated, which is formed by the effluent from the bypass shortcut nitrification tank I and the bypass anammox tank of the anammox bypass system, enters the anaerobic tank of the main stream treatment system, and the sludge from the bypass anammox tank of the anammox bypass system is discharged into the anaerobic tank of the main stream treatment system, and the nitrite nitrogen NO2 - -N and the anammox bacteria AAOB bacteria from the sludge of the bypass anammox tank coexist in the anaerobic tank, the dissolved oxygen DO in the anaerobic tank is controlled to be less than 0.2 mg / L, and the anammox reaction and denitrification reaction are simultaneously carried out in the anaerobic tank, and in the anammox reaction process in the anaerobic tank, the anammox bacteria AAOB competes with the denitrifying bacteria for the substrate to obtain the nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the sewage is utilized again to carry out the anammox reaction to remove the total nitrogen TN.

[0056] b) After the reaction in the anaerobic tank, the sludge-water mixture enters the anoxic tank, and the dissolved oxygen DO in the anoxic tank is controlled to be less than 0.3 mg / L, and in the anoxic tank, the anammox denitrification reaction occurs, and the anammox bacteria AAOB competes with the denitrifying bacteria for the substrate to obtain the nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the sewage is utilized again to carry out the anammox reaction to remove the total nitrogen TN.

[0057] c) After the reaction in the anoxic tank, the sludge-water mixture enters the low-oxygen aeration tank, and the dissolved oxygen DO in the low-oxygen aeration tank is controlled to be 0.1-0.5 mg / L, so that the shortcut nitrification reaction, the anammox reaction and the denitrification reaction are simultaneously carried out in the low-oxygen aeration tank, and the total nitrogen TN is removed by the combined processes of the shortcut nitrification process, the anammox process and the denitrification process in the low-oxygen aeration tank, and the sludge-water mixture in the low-oxygen aeration tank is backflowed to the anoxic tank, and the backflow ratio is 30%-100%.

[0058] d) After the reaction in the low-oxygen aeration tank, the sludge-water mixture enters the aerobic tank, and the dissolved oxygen DO in the aerobic tank is controlled to be 1-5 mg / L, so that the nitrification reaction occurs in the aerobic tank to remove the ammonia nitrogen NH4 + -N; and the generated nitrate nitrogen NO3 - -N is backflowed to the anoxic tank with the sludge-water mixture for denitrification removal, and the backflow ratio is 50%-200%.

[0059] e) After the reaction in the aerobic tank, the sludge-water mixture enters the secondary sedimentation tank for sludge-water separation, the clear liquid flows out of the main stream treatment system, and the sludge is backflowed to the anaerobic tank, and the backflow ratio is 30-100%.

[0060] Further, the total hydraulic retention time of the three reaction tanks of the anaerobic tank, the anoxic tank and the aerobic tank is 9-14 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank: anoxic tank: aerobic tank = (2.4-3.5): (2.6-4.5): (4.0-6.0).

[0061] Further, the total hydraulic retention time of the four reaction tanks of the anaerobic tank, the anoxic tank, the low-oxygen aeration tank and the aerobic tank is 9-14 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank: anoxic tank: low-oxygen aeration tank: aerobic tank = (2.4-3.5): (2.6-4.5): (1-2.5): (3-3.5).

[0062] Further, the reaction tank of the anaerobic ammonia oxidation bypass system further comprises an intermediate tank, the effluent of the bypass short-cut nitrification tank I flows into the intermediate tank, and the effluent of the intermediate tank flows into the bypass anaerobic ammonia oxidation tank.

[0063] The technical effect of the technical solution is:

[0064] (I) The short-cut nitrification process, the anaerobic ammonia oxidation process and the nitrification-denitrification process are combined for denitrification in the sewage treatment process, the total nitrogen TN removal capacity of the sewage treatment is improved, the energy consumption and the external carbon source are saved, and the total nitrogen TN of the sewage treatment is stably ensured to meet the standard.

[0065] (II) The technical solution realizes the stable supply of nitrite nitrogen NO2 - -N and anaerobic ammonia oxidation bacteria AAOB in the mainstream anaerobic ammonia oxidation process, and nitrite nitrogen NO2 - -N and anaerobic ammonia oxidation bacteria AAOB are two key factors for the effect of the mainstream anaerobic ammonia oxidation process. On the one hand, compared with the single nitrite nitrogen NO2 - -N source path in the prior art mainstream anaerobic ammonia oxidation, the nitrite nitrogen NO2 - -N in the technical solution process can be obtained from three paths: a) obtained from the effluent of the anaerobic ammonia oxidation bypass system; b) nitrate nitrogen NO3 - -N is denitrified into nitrite nitrogen NO2 - -N, anaerobic ammonia oxidation bacteria AAOB and denitrifying bacteria compete for; c) in the low-oxygen aeration tank, short-cut nitrifying bacteria AOB oxidize ammonia nitrogen NH4 + -N into nitrite nitrogen NO2 - -N, anaerobic ammonia oxidation bacteria AAOB and nitrite-oxidizing bacteria NOB, denitrifying bacteria compete for nitrite nitrogen NO2 - -N. The increase of the nitrite nitrogen NO2 - -N source path in the technical solution makes the nitrite nitrogen NO2 -The -N source is stable. On the other hand, by culturing the strain in the bypass side flow system and adding the bypass side flow anaerobic ammonia oxidation bacteria to the main flow system, a stable strain source is provided for the denitrification of the main flow anaerobic ammonia oxidation process. In summary, the technical scheme can realize the rapid start and stable operation of the anaerobic ammonia oxidation process in the main flow treatment system of the sewage.

[0066] (Three) The infrastructure of the anaerobic ammonia oxidation bypass system in the technical scheme can be a reinforced concrete structure; or a mobile steel structure, which can be used as a bypass system to rapidly start the anaerobic ammonia oxidation process in the main flow treatment system, realize the denitrification of nitrification-denitrification and short-cut nitrification, anaerobic ammonia oxidation, and then withdraw to provide for other sewage treatment projects for reuse. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 Preferred embodiment one of a combined process sewage treatment system.

[0068] Figure 2 Preferred embodiment two of a combined process sewage treatment system.

[0069] Figure 1 In the figure, 10-main flow treatment system, 11-anaerobic tank, 12-anoxic tank, 13-aerobic tank, 14-secondary sedimentation tank; 15-low-oxygen aeration tank; 20-anaerobic ammonia oxidation bypass system, 21-bypass short-cut nitrification tank I, 22-bypass anaerobic ammonia oxidation tank, 23-bypass short-cut nitrification tank II.

[0070] Figure 2 In the figure, 10'-main flow treatment system, 11'-anaerobic tank, 12'-anoxic tank, 13'-aerobic tank, 14'-secondary sedimentation tank; 15'-low-oxygen aeration tank; 20'-anaerobic ammonia oxidation bypass system, 21'-bypass short-cut nitrification tank I, 22'-bypass anaerobic ammonia oxidation tank, 23'-bypass short-cut nitrification tank II. DETAILED DESCRIPTION

[0071] The application will be described in further detail below with specific embodiments and drawings. However, it should not be understood that the above-mentioned subject matter of the application is limited to the following embodiments, and any technology realized based on the content of the application falls within the scope of the application.

[0072] Example one

[0073] As shown in Figure 1 A combined process sewage treatment system is applied in a sewage treatment plant in Guangxi, used for treating municipal sewage, and the ammonia nitrogen NH4 +-N is about 53 mg / L, total nitrogen is about 67 mg / L, and COD is about 356 mg / L. The reaction tank of the anaerobic ammonia oxidation bypass system (20) comprises a bypass short-cut nitrification tank I (21) and a bypass anaerobic ammonia oxidation tank (22), and the reaction tank of the main stream treatment system (10) comprises an anaerobic tank (11), an anoxic tank (12), an aerobic tank (13), and a secondary sedimentation tank (14) connected in sequence. Part of the effluent of the bypass short-cut nitrification tank I (21) flows into the anaerobic tank (11) of the main stream treatment system (10), another part of the effluent of the bypass short-cut nitrification tank I (21) flows into the bypass anaerobic ammonia oxidation tank (22), and the effluent of the bypass anaerobic ammonia oxidation tank (22) flows into the anaerobic tank (11) of the main stream treatment system (10) after being combined with the sewage to be treated. The sludge of the bypass anaerobic ammonia oxidation tank (22) is discharged into the anaerobic tank (11) at the beginning of the operation stage of the combined process sewage treatment system. The effluent of the anaerobic tank (11) flows into the anoxic tank (12), the effluent of the anoxic tank (12) flows into the aerobic tank (13), the effluent of the aerobic tank (13) flows into the secondary sedimentation tank (14), and part of the effluent of the aerobic tank (13) is returned to the anoxic tank (12). The sludge of the secondary sedimentation tank (14) is returned to the anaerobic tank (11).

[0074] The process of the combined process sewage treatment system comprises a start-up stage and an operation stage, and the specific process steps are as follows:

[0075] In the start-up stage, the anaerobic ammonia oxidation bypass system (20) performs short-cut nitrification reaction to generate nitrite nitrogen NO2 - -N and cultivating anaerobic ammonia oxidation AAOB bacteria. The anaerobic ammonia oxidation bypass system (20) comprises the following steps in the start-up stage:

[0076] a) Bypass short-cut nitrification tank I and bypass anaerobic ammonia oxidation tank inoculation: short-cut nitrification bacteria AOB seed sludge is put into the bypass short-cut nitrification tank I (21), and the inoculation amount of bacteria is MLSS≈2000 mg / L. Anaerobic ammonia oxidation bacteria seed AAOB seed sludge is put into the bypass anaerobic ammonia oxidation tank (22), and the inoculation amount of bacteria is MLSS≈800 mg / L.

[0077] b) Bypass short-cut nitrification tank I (21) performs short-cut nitrification reaction: the sewage to be treated of the main stream treatment system (10) enters the bypass short-cut nitrification tank I (21). After the water inlet is completed, ammonia nitrogen NH4 + -N compound is supplemented into the bypass short-cut nitrification tank I (21) according to the ammonia nitrogen content in the sewage, the air blower is turned on for aeration, the dissolved oxygen DO is controlled to be less than or equal to 1.5 mg / L, the short-cut nitrification reaction is performed, and the ammonia nitrogen NH4 + -N is completely converted into nitrite nitrogen NO2 - -N. When the volume of ammonia nitrogen NH4+ When N < 1 mg / L, the reaction ends, and the water is discharged after standing and precipitation, and the total water discharge is 30-60% of the volume. After the water is discharged, the next reaction cycle is entered;

[0078] c) Anaerobic ammonia oxidation by-pass tank (22) for anaerobic ammonia oxidation reaction: part of the effluent from the by-pass short-cut nitrification tank I (21) enters the by-pass anaerobic ammonia oxidation tank (22), and part of the effluent enters the anaerobic tank (11) of the main stream treatment system (10). According to the total nitrogen TN removal load of the by-pass anaerobic ammonia oxidation AAOB bacteria, the by-pass anaerobic ammonia oxidation tank (22) is added with ammonia nitrogen NH4 + -N compound, so that the volume of ammonia nitrogen NH4 + -N: nitrite nitrogen NO2 - -N ≈ 1:1.32; when the volume of ammonia nitrogen NH4 + -N < 10 mg / L, the reaction ends, and the water is discharged after standing and precipitation, and the total water discharge is 30-60% of the volume. After the water is discharged, the next reaction cycle is entered;

[0079] During the start-up phase of the anaerobic ammonia oxidation by-pass system (20), the sludge in the by-pass anaerobic ammonia oxidation tank (22) is not discharged into the main stream treatment system (10), and the main stream treatment system (10) is denitrified in a nitrification-denitrification manner. The main stream treatment system (10) in the start-up phase includes the following process steps:

[0080] a) The mixed wastewater formed by the effluent of the by-pass short-cut nitrification tank I (21) and the by-pass anaerobic ammonia oxidation tank (22) of the anaerobic ammonia oxidation by-pass system (20) enters the anaerobic tank (11) of the main stream treatment system (10), and the dissolved oxygen DO in the anaerobic tank (11) is controlled to be less than 0.2 mg / L, so that the denitrification reaction in the anaerobic tank (11) is carried out;

[0081] b) The mixed wastewater after the denitrification reaction in the anaerobic tank (11) of step a) enters the anoxic tank (12), and the dissolved oxygen DO in the anoxic tank (12) is controlled to be less than 0.3 mg / L, so that the denitrification reaction in the anoxic tank (12) is carried out;

[0082] c) The mixed wastewater after the denitrification reaction in the anoxic tank (12) of step b) enters the aerobic tank (13), and the dissolved oxygen DO in the aerobic tank (13) is controlled to be 1-5 mg / L, so that the nitrification reaction in the aerobic tank (13) is carried out, and the nitrifying bacteria (NOB) oxidize the ammonia nitrogen NH4 + -N to nitrate nitrogen NO3 - -N, and the ammonia nitrogen NH4 + -N; the generated nitrate nitrogen NO3 -- N backflow to the anoxic tank (12) for denitrification removal, and the sludge-water mixture backflow ratio is 50-300%;

[0083] d) The sludge-water mixture after the nitrification reaction in the aerobic tank (13) in step c) enters the secondary sedimentation tank (14) for sludge-water separation, the clear liquid flows out of the main stream treatment system (10) by itself, and the sludge backflows to the anaerobic tank (11) with a backflow ratio of 30%-100%;

[0084] The total hydraulic retention time of the anaerobic tank (11), the anoxic tank (12) and the aerobic tank (13) is 14 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank (11): anoxic tank (12): aerobic tank (13)=3.5:4.5:6.0.

[0085] When the nitrite nitrogen NO2 - When the nitrite nitrogen NO2

[0086] In the running phase, the anammox AAOB bacteria cultivated in the startup phase of the anammox bypass system (20) are discharged into the anaerobic tank (11) of the main stream treatment system (10) with the sludge of the anammox bypass tank (22), and in the main stream treatment system (10), the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexistence of nitrification-denitrification and anammox process, and the nitrification-denitrification and anammox process is combined to run for denitrification;

[0087] In the running phase, the anammox bypass system (20) includes the following process steps:

[0088] a) Short-cut nitrification reaction in the bypass short-cut nitrification tank I (21): the wastewater to be treated enters the bypass short-cut nitrification tank I (21), and according to the ammonia nitrogen content in the wastewater, ammonia nitrogen NH4 + -N compounds are supplemented to the bypass short-cut nitrification tank I (21), aeration is performed after the water inlet is completed, the dissolved oxygen DO is controlled to be less than or equal to 1.5 mg / L, and short-cut nitrification reaction is performed; the short-cut nitrification converts all ammonia nitrogen NH4 + -N into nitrite nitrogen NO2 - -N; after the reaction is completed, standing, sedimentation and water outlet are performed, and the water outlet flows into the bypass anammox tank (22) and the reaction tank of the main stream treatment system (10) respectively, and the total water outlet amount is 30-60% of the volume, and after the water outlet is completed, the next reaction cycle is waited for;

[0089] b) Bypass anaerobic ammonia oxidation tank (22) to carry out anaerobic ammonia oxidation reaction: part of the short-cut nitrification tank I (21) effluent flows into the bypass anaerobic ammonia oxidation tank (22), and according to the total nitrogen TN removal load of the bypass anaerobic ammonia oxidation AAOB bacteria, a proper amount of ammonia nitrogen NH4 + -N containing compound is added to the bypass anaerobic ammonia oxidation tank (22), so that the volume of ammonia nitrogen NH4 + -N: nitrite nitrogen NO2 - -N≈1:1.32; stirring to fully carry out anaerobic ammonia oxidation reaction; after the reaction is completed, standing, precipitation, effluent to the reaction tank of the main stream treatment system (10), and the effluent volume is 30-60% of the volume; after the effluent is completed, waiting for entering the next reaction period;

[0090] During the running stage, the main stream treatment system (10) process includes the following process steps:

[0091] a) The mixed wastewater formed by the effluent of the bypass short-cut nitrification tank I (21) and the bypass anaerobic ammonia oxidation tank (22) of the anaerobic ammonia oxidation bypass system (20) enters the anaerobic tank (11) of the main stream treatment system (10), and the sludge of the bypass anaerobic ammonia oxidation tank (22) of the anaerobic ammonia oxidation bypass system (20) is discharged into the anaerobic tank (11) of the main stream treatment system (10), and the nitrite nitrogen NO2 - -N from the bypass anaerobic ammonia oxidation tank (22) and the anaerobic ammonia oxidation bacteria AAOB bacteria from the sludge of the bypass anaerobic ammonia oxidation tank (22) exist in the anaerobic tank (11) at the same time, the dissolved oxygen DO in the anaerobic tank (11) is controlled to be less than 0.2 mg / L, so that the anaerobic ammonia oxidation reaction and the denitrification reaction in the anaerobic tank (11) are carried out at the same time, and the anaerobic ammonia oxidation reaction process in the anaerobic tank (11): the anaerobic ammonia oxidation AAOB bacteria compete with the denitrifying bacteria for the substrate to obtain nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the wastewater is utilized again to carry out anaerobic ammonia oxidation reaction to remove total nitrogen TN.

[0092] b) After the reaction of the anaerobic tank (11), the sludge-water mixture enters the anoxic tank (12), and the dissolved oxygen DO in the anoxic tank (12) is controlled to be less than 0.3 mg / L; in the anoxic tank (12), the anaerobic ammonia oxidation denitrification reaction also occurs, the anaerobic ammonia oxidation AAOB bacteria compete with the denitrifying bacteria for the substrate to obtain nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the wastewater is utilized again to carry out anaerobic ammonia oxidation reaction to remove total nitrogen TN.

[0093] c) After the reaction of the anoxic tank (12), the sludge-water mixture enters the aerobic tank (13), and the dissolved oxygen DO in the aerobic tank (13) is controlled to be 1-5 mg / L, so that the nitrification reaction occurs in the aerobic tank (13), and the nitrifying bacteria (NOB) oxidize the residual ammonia nitrogen NH4 + -N to nitrate nitrogen NO3 - -N, and the ammonia nitrogen NH4 + -N is removed. - -N is removed. + -N, and the sludge-water mixture is returned to the anoxic tank (12) again to remove the generated nitrate nitrogen NO3

[0094] d) After the reaction of the aerobic tank (13), the sludge-water mixture enters the secondary sedimentation tank (14) for sludge-water separation, the clear liquid flows out of the main flow treatment system (10) by itself, and the sludge is returned to the anaerobic tank (11) at a return ratio of 30%-100%.

[0095] The total hydraulic retention time of the anaerobic tank (11), the anoxic tank (12) and the aerobic tank (13) is 14 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank (11): anoxic tank (12): aerobic tank (13)=3.5:4.5:6.0.

[0096] When the total nitrogen in the effluent meets the Class A standard of the "GB 18918-2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant" for 12 consecutive days, the anaerobic ammonia oxidation of the main flow treatment system (10) is successfully started. The denitrification method of the main flow treatment system changes from a single nitrification-denitrification process to a nitrification-denitrification and anaerobic ammonia oxidation coexisting process.

[0097] During the operation stage of the main flow treatment system (10), the anaerobic ammonia oxidation reaction condition and the ammonia nitrogen NH4 + -N concentration level of the influent are monitored to adjust the amount of anaerobic ammonia oxidation bacteria AAOB bacteria delivered from the anaerobic ammonia oxidation bypass system (20) to the main flow treatment system (10).

[0098] After the combined process wastewater treatment system is continuously operated for 42 days, the ammonia nitrogen NH4 + -N and total nitrogen TN change comparison is as follows (taking the average value of the data for 42 consecutive days)

[0099] Table 1 Comparison of combined process wastewater treatment and single process wastewater treatment

[0100] Item ammonium (NH4 + -N) Total nitrogen (TN) Unit mg / L mg / L National mandatory standard "GB 18918-2002" level A standard 5 15 Single denitrification process 3.67 26.38 (over standard) Combined denitrification process 0.05 7.56 Percentage of reduction 98.6% 71.3%

[0101] As shown in Table 1 above, after the combined process wastewater treatment system of the technical solution is used, the total nitrogen in the effluent stably meets the Class A standard of the national mandatory standard "GB 18918-2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant". The ammonia nitrogen NH4+ -N is reduced from 3.67 mg / L to 0.05 mg / L by using the single denitrification process, the effluent ammonia nitrogen NH4 + -N is reduced by 98.6%; the effluent total nitrogen TN is reduced from 26.38 mg / L to 7.56 mg / L by using the single denitrification process, the effluent total nitrogen TN is reduced by 71.3%.

[0102] Example Two

[0103] As Figure 2 shown, a combined process wastewater treatment system is applied in a wastewater treatment plant in an industrial concentrated area of a city in Guangxi. The wastewater treated by the wastewater treatment plant includes domestic wastewater and reeling silk byproduct processing wastewater. The domestic wastewater directly enters the combined process wastewater treatment system, and the ammonia nitrogen NH4 + -N is about 46 mg / L, the total nitrogen TN is about 60 mg / L, and the COD is about 310 mg / L. The reeling silk byproduct processing wastewater first undergoes decarbonization pretreatment and then enters the combined process wastewater treatment system. The pretreated reeling silk byproduct processing wastewater NH4 +-N about 1600 mg / L, total nitrogen TN about 1800 mg / L, COD about 425 mg / L. The reaction tank of the anaerobic ammonia oxidation bypass system (20') comprises a bypass short-cut nitrification tank I (21'), a bypass short-cut nitrification tank II (23') and a bypass anaerobic ammonia oxidation tank (22'), the reaction tank of the main flow treatment system (10') comprises an anaerobic tank (11'), an anoxic tank (12'), a low-oxygen aeration tank (15'), an aerobic tank (13') and a secondary sedimentation tank (14') connected in sequence, a part of the effluent of the bypass short-cut nitrification tank I (21') flows into the bypass short-cut nitrification tank II (23'), another part of the effluent of the bypass short-cut nitrification tank I (21') flows into the bypass anaerobic ammonia oxidation tank (22'), the effluent of the bypass anaerobic ammonia oxidation tank (22') flows into the anaerobic tank (11') of the main flow treatment system (10'), the effluent of the bypass short-cut nitrification tank II (23') flows into the anaerobic tank (11') of the main flow treatment system (10'), the sludge of the bypass anaerobic ammonia oxidation tank (22') is discharged into the anaerobic tank (11') of the main flow treatment system (10') at the beginning of the operation stage of the combined process wastewater treatment system, the effluent of the anaerobic tank (11') of the main flow treatment system (10') flows into the anoxic tank (12'), the effluent of the anoxic tank (12') flows into the low-oxygen aeration tank (15'), the effluent of the low-oxygen aeration tank (15') flows into the aerobic tank (13'), the effluent of the aerobic tank (13') flows into the secondary sedimentation tank (14'), meanwhile, part of the sludge-water mixture of the low-oxygen aeration tank (15') is returned to the anoxic tank (12'), part of the sludge-water mixture of the aerobic tank (13') is returned to the anoxic tank (12'), and the sludge of the secondary sedimentation tank (14') is returned to the anaerobic tank (11').

[0104] The process of the combined process wastewater treatment system comprises a start-up stage and an operation stage, and the specific process steps are as follows:

[0105] In the start-up stage, the anaerobic ammonia oxidation bypass system (20') performs short-cut nitrification to generate nitrite nitrogen NO2 - -N and cultivating anaerobic ammonia oxidation AAOB bacteria, the anaerobic ammonia oxidation bypass system (20') comprises the following steps in the start-up stage:

[0106] a) Bacterial inoculation of the bypass short-cut nitrification tank I (21'), the bypass short-cut nitrification tank II (23') and the bypass anaerobic ammonia oxidation tank (22'): short-cut nitrification bacteria AOB seed sludge is respectively put into the bypass short-cut nitrification tank I (21') and the bypass short-cut nitrification tank II (23'), the bacterial inoculation amount MLSS≈1500-3500 mg / L, anaerobic ammonia oxidation bacteria seed AAOB seed sludge is put into the bypass anaerobic ammonia oxidation tank (22'), the bacterial inoculation amount MLSS>500 mg / L;

[0107] b) Bypass short-cut nitrification tank I (21') to carry out short-cut nitrification reaction: the decarburization pretreated silk reeling by-product processing wastewater is used as the influent of the bypass short-cut nitrification tank I (21') to start the anaerobic ammonia oxidation bypass system (20'), and the dissolved oxygen DO is less than or equal to 1.5 mg / L; the influent is stirred at the same time, after the influent is finished, the air blower is opened to aerate, and the short-cut nitrification reaction is carried out, part of the ammonia nitrogen NH4 + -N is converted into nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N in the effluent is controlled to be less than or equal to 10 mg / L, and the reaction is completed. - -N=1:1~1:1.3, after the aeration is finished, standing, precipitation, and the effluent is respectively discharged to the bypass short-cut nitrification tank II (23') and the bypass anaerobic ammonia oxidation tank (22'), the total effluent volume is 30%~60% of the volume, and after the effluent is completed, the next reaction cycle is entered;

[0108] c) A part of the bypass short-cut nitrification tank I (21') effluent flows into the bypass anaerobic ammonia oxidation tank (22') to carry out the anaerobic ammonia oxidation reaction, the anaerobic ammonia oxidation reaction is fully stirred, and when the ammonia nitrogen NH4 + -N in the bypass anaerobic ammonia oxidation tank (22') is less than 10 mg / L, the reaction is completed, standing, precipitation, and the effluent is discharged to the reaction tank of the main stream sewage treatment system (10'), the effluent volume is 30%~60% of the volume, and after the effluent is completed, the next reaction cycle is entered;

[0109] d) Another part of the bypass short-cut nitrification tank I (21') effluent flows into the bypass short-cut nitrification tank II (23') to carry out the short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + -N is completely converted into nitrite nitrogen NO2 - -N, after the reaction is completed, standing, precipitation, and the effluent is discharged to the reaction tank of the main stream sewage treatment system (10'), the effluent volume is 30%~60% of the volume, and after the effluent is completed, the next reaction cycle is entered;

[0110] When the nitrite nitrogen NO2 - -N generation rate of the bypass short-cut nitrification tank I (21') and the bypass short-cut nitrification tank II (23') in the anaerobic ammonia oxidation bypass system (20') is greater than 10 mg / L·h, and the anaerobic ammonia oxidation bacteria AAOB amount MLSS of the bypass anaerobic ammonia oxidation tank (22') is greater than 1500 mg / L, the combined process sewage treatment system is started and completed.

[0111] In the starting stage, the sludge in the bypass anaerobic ammonia oxidation tank (22') is not discharged into the main stream treatment system (10'), the main stream treatment system (10') carries out denitrification in the nitrification-denitrification and short-cut nitrification modes, and includes the following process steps:

[0112] a) The mixed sewage formed by the effluent of the by-pass shortcut nitrification tank II (23') and the by-pass ANAMMOX tank (22') of the by-pass ANAMMOX system (20') is introduced into the anaerobic tank (11') of the main stream treatment system (10'), and the dissolved oxygen DO in the anaerobic tank (11') is controlled to be less than 0.2 mg / L, so that the denitrification reaction is carried out in the anaerobic tank (11');

[0113] b) The mixed sewage after the denitrification reaction in the anaerobic tank (11') of step a) is introduced into the anoxic tank (12'), and the dissolved oxygen DO in the anoxic tank (12') is controlled to be less than 0.3 mg / L, so that the denitrification reaction is carried out in the anoxic tank (12');

[0114] c) The sewage after the reaction in the anoxic tank (12') of step b) is introduced into the low-oxygen aeration tank (15'), and the dissolved oxygen DO in the low-oxygen aeration tank (15') is controlled to be 0.1-0.5 mg / L, so that the shortcut nitrification reaction and the denitrification reaction are carried out synchronously in the low-oxygen aeration tank (15'), the short-cut nitrifying bacteria (AOB) oxidize the ammonia nitrogen NH4 + -N to nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N is generated, the nitrite nitrogen NO2 - -N is further denitrified to nitrogen N2, and the total nitrogen TN is removed, and the sludge-water mixture in the low-oxygen aeration tank (15') is returned to the anoxic tank (12') at a return ratio of 30%-100%;

[0115] d) The mixed sewage after the reaction in the low-oxygen aeration tank (15') of step c) is introduced into the aerobic tank (13'), and the dissolved oxygen DO in the aerobic tank (13') is controlled to be 1-5 mg / L, so that the nitrification reaction is carried out in the aerobic tank (13'), and the nitrifying bacteria (NOB) oxidize the ammonia nitrogen NH4 + -N to nitrate nitrogen NO3 - -N, the ammonia nitrogen NH4 + -N is generated, the nitrate nitrogen NO3 - -N is returned to the anoxic tank (12') with the sludge-water mixture for denitrification removal, and the return ratio of the sludge-water mixture is 50%-200%;

[0116] e) The sludge-water mixture after the nitrification reaction in the aerobic tank (13') of step d) is introduced into the secondary sedimentation tank (14') for sludge-water separation, the clear liquid is discharged from the main stream treatment system (10') by gravity, and the sludge is returned to the anaerobic tank (11') at a return ratio of 30%-100%.

[0117] The total hydraulic retention time of the anaerobic tank (11'), anoxic tank (12'), low-oxygen aeration tank (15') and aerobic tank (13') is 10 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank (11'): anoxic tank (12'): low-oxygen aeration tank (15'): aerobic tank (13') = 2.5:3.2:1.8:2.5.

[0118] During the running stage, the anaerobic ammonia oxidation bypass system (20') includes the following process steps:

[0119] a) The byproduct processing wastewater after decarburization pretreatment enters the bypass short-cut nitrification tank I (21') to perform short-cut nitrification reaction, and part of the ammonia nitrogen NH4 + -N is converted into nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the effluent is controlled: nitrite nitrogen NO2 - -N = 1:1~1:1.3, the reaction is ended, and the water is respectively discharged to the bypass anaerobic ammonia oxidation tank (22') and the bypass short-cut nitrification tank II (23') after standing and sedimentation, and the total effluent volume is 30-60% of the volume. After the effluent is completed, the next reaction cycle is waited for.

[0120] b) Part of the bypass short-cut nitrification tank I (21') effluent flows into the bypass anaerobic ammonia oxidation tank (22') to perform anaerobic ammonia oxidation reaction, and stirring is performed to fully perform the anaerobic ammonia oxidation reaction. When the ammonia nitrogen NH4 + -N in the bypass anaerobic ammonia oxidation tank (22') is less than 10 mg / L, the reaction is ended, and the water is discharged to the reaction tank of the main wastewater treatment system (10') after standing and sedimentation, and the effluent volume is 30-60% of the volume. After the effluent is completed, the next reaction cycle is waited for;

[0121] c) Another part of the bypass short-cut nitrification tank I (21') effluent flows into the bypass short-cut nitrification tank II (23') to perform short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + -N is converted into nitrite nitrogen NO2 - -N, and after the reaction is ended, the water is discharged to the reaction tank of the main wastewater treatment system (10') after standing and sedimentation, and the effluent volume is 30-60% of the volume. After the effluent is completed, the next reaction cycle is waited for.

[0122] In the running stage, the anammox bacteria cultivated in the start-up stage of the anammox bypass system (20') are discharged into the anaerobic tank (11') of the mainstream treatment system (10') along with the sludge of the anammox tank (22'), and in the mainstream treatment system (10'), the denitrification process is gradually changed from the coexistence of nitrification-denitrification and shortcut nitrification to the coexistence of nitrification-denitrification, shortcut nitrification and anammox, and the nitrification-denitrification, shortcut nitrification and anammox processes are combined to remove total nitrogen TN, and the process steps include the following:

[0123] a) the mixed wastewater formed by the effluent of the bypass shortcut nitrification tank II (23') and the bypass anammox tank (22') of the anammox bypass system (20') is introduced into the anaerobic tank (11') of the mainstream treatment system (10'), the sludge of the bypass anammox tank (22') of the anammox bypass system (20') is discharged into the anaerobic tank (11') of the mainstream treatment system (10'), and the nitrite nitrogen NO2 - -N from the effluent of the bypass shortcut nitrification tank II (23') and the bypass anammox tank (22') and the anammox bacteria AAOB from the sludge of the bypass anammox tank (22') coexist in the anaerobic tank (11'), the dissolved oxygen DO in the anaerobic tank (11') is controlled to be less than 0.2 mg / L, and the anammox reaction and the denitrification reaction are simultaneously performed in the anaerobic tank (11'), the anammox reaction process in the anaerobic tank (11') is that the anammox bacteria AAOB and the denitrifying bacteria compete for the substrate to obtain the nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the wastewater is used to perform the anammox reaction to remove the total nitrogen TN.

[0124] b) after the reaction of the anaerobic tank (11'), the sludge-water mixture is introduced into the anoxic tank (12'), the dissolved oxygen DO in the anoxic tank (12') is controlled to be less than 0.3 mg / L, and in the anoxic tank (12'), the anammox denitrification reaction occurs, the anammox bacteria AAOB and the denitrifying bacteria compete for the substrate to obtain the nitrite nitrogen NO2 - -N, and the ammonia nitrogen NH4 + -N in the wastewater is used to perform the anammox reaction to remove the total nitrogen TN.

[0125] c) after the reaction of the anoxic tank (12'), the sludge-water mixture is introduced into the low-oxygen aeration tank (15'), the dissolved oxygen DO in the low-oxygen aeration tank (15') is controlled to be 0.1-0.5 mg / L, the shortcut nitrification reaction, the anammox reaction and the denitrification reaction are simultaneously performed in the low-oxygen aeration tank (15'), and the shortcut nitrification process, the anammox process and the denitrification process are combined to remove the total nitrogen TN in the low-oxygen aeration tank (15'), and the sludge-water mixture in the low-oxygen aeration tank (15') is backflowed to the anoxic tank (12') at a backflow ratio of 30%-100%.

[0126] d) After the low-oxygen aeration tank (15') reaction, the sludge-water mixture enters the aerobic tank (13'), and the dissolved oxygen DO in the aerobic tank (13') is controlled to be 1-5 mg / L, so that nitrification reaction occurs in the aerobic tank (13') to remove ammonia nitrogen NH4 + -N, and the generated nitrate NO3 - -N is returned to the anoxic tank (12') with the sludge-water mixture, and the return ratio is 50%-200%.

[0127] e) After the sludge-water mixture in the aerobic tank (13') reaction, the sludge-water mixture enters the secondary sedimentation tank (14') for sludge-water separation, the clear liquid flows out of the main stream treatment system (10'), and the sludge returns to the anaerobic tank (11') with a return ratio of 30-100%.

[0128] The total hydraulic retention time of the anaerobic tank (11'), the anoxic tank (12'), the low-oxygen aeration tank (15'), and the aerobic tank (13') is 10 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank (11'): anoxic tank (12'): low-oxygen aeration tank (15'): aerobic tank (13') = 2.5:3.2:1.8:2.5.

[0129] When the total nitrogen in the effluent meets the Class A standard of the "GB18918-2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant" for 12 consecutive days, the anaerobic ammonia oxidation of the main stream wastewater treatment system (10') is successfully started. The denitrification mode of the main stream wastewater treatment system is changed from nitrification-denitrification and short-cut nitrification to nitrification-denitrification, short-cut nitrification and anaerobic ammonia oxidation coexistence process.

[0130] During the operation stage of the main stream wastewater treatment system (10'), the anaerobic ammonia oxidation reaction condition and the ammonia nitrogen NH4 + -N concentration level of the influent are monitored to adjust the amount of anaerobic ammonia oxidation bacteria AAOB bacteria delivered by the anaerobic ammonia oxidation bypass system (20') to the main stream wastewater treatment system (10').

[0131] After the combined process wastewater treatment system is continuously operated for 45 days, the effluent ammonia nitrogen NH4 + -N and total nitrogen TN change comparison is as follows (taking the average value of the data for 45 consecutive days)

[0132] Table 2 Comparison of combined process wastewater treatment and single process wastewater treatment

[0133] Item Total nitrogen (TN) ammonium (NH4 + -N) Unit mg / L mg / L GB 18918-2002 level A standard 15 5 Single denitrification process 32.28 (over standard) 5.61 Combined denitrification process 9.43 0.25 Percentage of reduction 70.8% 95.5%

[0134] As shown in Table 2 above, after using the combined process wastewater treatment system of the technical solution, the total nitrogen in the effluent stably meets the Class A standard of the "GB18918-2002 Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant". The effluent ammonia nitrogen NH4+ N is reduced from 5.61 mg / L in the original single denitrification process to 0.25 mg / L, which is reduced by 95.5%. The total nitrogen TN in the effluent is reduced from 32.28 mg / L in the original single denitrification process to 9.43 mg / L, which is reduced by 70.8%.

[0135] The above merely describes preferred embodiments of the present application and should not be used to limit the present application. This should not be understood as the subject matter protected by the present application being limited to the above embodiments only, and any modification, equivalent replacement, improvement, etc. made by those of ordinary skill in the art without creativity, within the spirit and principle of the present application, should be included in the protection scope of the present application.

Claims

1. A combined process wastewater treatment system characterized by: The combined wastewater treatment system includes an anaerobic ammonia oxidation bypass system and a mains treatment system. The anaerobic ammonia oxidation bypass system includes several connected reaction tanks. Each reaction tank in the anaerobic ammonia oxidation bypass system is equipped with an inlet and an outlet. The reaction tanks in the anaerobic ammonia oxidation bypass system include bypass short-cut nitrification tank I and bypass anaerobic ammonia oxidation tank connected in series, and also include bypass short-cut nitrification tank II. A portion of the effluent from bypass short-cut nitrification tank I flows into bypass short-cut nitrification tank II, and another portion of the effluent from bypass short-cut nitrification tank I flows into bypass anaerobic ammonia oxidation tank. The main treatment system includes a reaction tank consisting of an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank connected in sequence. The effluent from the anaerobic tank flows into the anoxic tank, the effluent from the anoxic tank flows into the aerobic tank, and the effluent from the aerobic tank flows into the secondary sedimentation tank. Simultaneously, a portion of the effluent from the aerobic tank is returned to the anoxic tank, and the sludge from the secondary sedimentation tank is returned to the anaerobic tank. The main treatment system also includes a low-oxygen aeration tank located between the anoxic tank and the aerobic tank. The effluent from the anoxic tank flows into the low-oxygen aeration tank, the effluent from the low-oxygen aeration tank flows into the aerobic tank, and a portion of the effluent from the low-oxygen aeration tank is returned to the anoxic tank. The effluent of the short-cut nitrification tank II in the anaerobic ammonia oxidation bypass system and the effluent of the anaerobic ammonia oxidation tank in the bypass system both flow into the anaerobic tank of the main stream treatment system, providing nitrous nitrogen NO2 for the main stream treatment system - -N; the sludge of the anaerobic ammonia oxidation tank in the bypass system is discharged into the anaerobic tank at the beginning of the operation stage of the combined process wastewater treatment system, or is discharged into the anaerobic tank and the anoxic tank at the same time, providing anaerobic ammonia oxidation bacteria AAOB for the main stream treatment system.

2. A process method for a combined wastewater treatment system as described in claim 1, comprising a start-up phase and an operation phase: a) at the start-up stage: the anammox bypass system carries out short-cut nitrification reaction to generate nitrite nitrogen NO2 - -N and cultivating anammox AAOB bacteria, when the anammox bypass system transports the effluent with nitrite nitrogen NO2 - -N generation rate > 10 mg / L·h, and the MLSS of anammox AAOB bacteria in the anammox bypass system > 1500 mg / L, the combined process wastewater treatment system is completed; b) During the operation phase: The anaerobic ammonia oxidation bypass system delivers the anaerobic ammonia oxidation (AAOB) bacteria cultivated in the start-up phase (a) to the main treatment system connected to it through sludge discharge, thereby activating the anaerobic ammonia oxidation denitrification process in the main treatment system and forming a combined denitrification process with the original denitrification process of the main treatment system.

3. The process method of the combined process wastewater treatment system according to claim 2, characterized in that: During the start-up phase (a), the anaerobic ammonia oxidation bypass system includes the following steps: a) Inoculation of bacteria in bypass short-cut nitrification tank I, bypass short-cut nitrification tank II and bypass anammox tank: Take short-cut nitrifying bacteria AOB seed sludge and put it into bypass short-cut nitrification tank I and bypass short-cut nitrification tank II respectively, with a seed sludge MLSS≈1500~3500mg / L; take anammox bacteria AAOB seed sludge and put it into bypass anammox tank, with a seed sludge MLSS>100mg / L; b) bypass short-cut nitrification tank I to carry out short-cut nitrification reaction: taking the high ammonia-nitrogen wastewater after decarburization pretreatment as the influent of the bypass short-cut nitrification tank I to start the bypass system, the dissolved oxygen DO is less than or equal to 1.5 mg / L; the influent is stirred at the same time, after the influent is finished, the air blower is opened to aerate, the short-cut nitrification reaction is carried out, part of the ammonia-nitrogen NH4 + -N is converted into nitrite nitrogen NO2 - -N, the ammonia-nitrogen NH4 + -N in the effluent is controlled to be less than or equal to 0.5 mg / L; the nitrite nitrogen NO2 - -N=1:1~1:1.3, after the aeration is finished, standing, precipitation, and respectively effluent to the bypass short-cut nitrification tank II and the bypass ANAMMOX tank, the total effluent amount is 30~60% of the volume, after the effluent is finished, the next reaction cycle is entered; c) A part of the effluent from the short-cut nitrification tank I is fed into the shortcut ANAMMOX tank for ANAMMOX reaction. The ANAMMOX reaction is fully stirred. When the ammonia nitrogen NH4 + The reaction is ended when the ammonia nitrogen NH4 -N < 10 mg / L. The reaction is ended, and the effluent is precipitated and fed into the reaction tank of the main wastewater treatment system. The effluent volume is 30-60% of the tank volume. After the effluent is completed, the next reaction cycle is started. d) Another part of the effluent from the bypass short-cut nitrification tank I flows into the bypass short-cut nitrification tank II for short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + - N is all converted into nitrite N02 - - N, after the reaction, standing, precipitation, effluent to the reaction tank of the main wastewater treatment system, the effluent volume is 30-60% of the volume, and after the effluent, waiting for entering the next reaction cycle; Sludge from the bypass ANAMMOX tank is not discharged into the main stream treatment system, when the nitrite nitrogen NO2 - The combined process wastewater treatment system is completed when the bypass shortcut nitrification tank I and the bypass shortcut nitrification tank II in the ANAMMOX bypass system have a nitrite nitrogen NO2 - generation rate > 10 mg / L·h, and the AAOB bacteria MLSS in the bypass ANAMMOX tank > 1500 mg / L.

4. The process method of a combined process wastewater treatment system according to claim 2, characterized in that: During the start-up phase (a) of the main treatment system, sludge from the bypass anaerobic ammonia oxidation tank is not discharged into the main treatment system. The denitrification method of the main treatment system gradually changes from the original single nitrification-denitrification process to a combined nitrification-denitrification and short-cut nitrification process, including the following process steps: The wastewater to be treated is combined with the effluent from the bypass short-cut nitrification tank I or bypass short-cut nitrification tank II of the anaerobic ammonia oxidation bypass system and the effluent from the bypass anaerobic ammonia oxidation tank to form a mixed wastewater that enters the anaerobic tank of the main treatment system. The dissolved oxygen (DO) in the anaerobic tank is controlled to be less than 0.2 mg / L, so that denitrification reaction can take place in the anaerobic tank. b) The mixed sewage after the anaerobic tank denitrification reaction in step a) enters the anoxic tank, and the dissolved oxygen DO in the anoxic tank is controlled to be less than 0.3 mg / L, and the denitrification reaction occurs in the anoxic tank; c) The sewage after step b) is introduced into a low-oxygen aeration tank, the dissolved oxygen DO in the low-oxygen aeration tank is controlled to be 0.1-0.5 mg / L, the short-cut nitrification and denitrification in the low-oxygen aeration tank are simultaneously carried out, the short-cut nitrification bacteria (AOB) oxidize the ammonia nitrogen NH4 + -N to nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N is removed, the generated nitrite nitrogen NO2 - -N is denitrified to nitrogen N2 again, the total nitrogen TN is removed, and the sludge-water mixture in the low-oxygen aeration tank is backflowed to the anoxic tank, the backflow ratio being 30%-100%. d) The mixed sewage after the step c) low oxygen aeration tank reaction enters the oxygen tank, controls the dissolved oxygen DO = 1-5 mg / L in the oxygen tank, makes the nitrification reaction in the oxygen tank, and the nitrification bacteria (NOB) oxidizes the ammonia nitrogen NH4 + -N in the sewage into nitrate NO3 - -N, removes the ammonia nitrogen NH4 + -N; the generated nitrate NO3 - -N returns to the anoxic tank with the sludge-water mixture for denitrification removal, and the sludge-water mixture reflux ratio is 50-200%. e) The sludge-water mixture after the nitrification reaction in the aerobic tank in step d) enters the secondary sedimentation tank for sludge-water separation, the clear liquid flows out of the main stream treatment system, and the sludge is returned to the anaerobic tank with a return ratio of 30% to 100%.

5. The process method of the combined process wastewater treatment system according to claim 2, characterized in that: In the b) operation phase, the anaerobic ammonia oxidation bypass system comprises the following process steps: a) High ammonia nitrogen wastewater enters the bypass shortcut nitrification tank I for shortcut nitrification reaction, and part of the ammonia nitrogen NH4 + -N is converted into nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N in the effluent is controlled to be less than 1 mg / L - -N=1:1~1:1.3, the reaction is ended, and the static state, precipitation, and separate effluent to the bypass anaerobic ammonia oxidation tank and the bypass shortcut nitrification tank II are performed, and the total effluent volume is 30~60% of the volume, and after the effluent is completed, waiting for entering the next reaction cycle is performed. b) A part of the effluent from the short-cut nitrification tank I is fed into the shortcut ANAMMOX tank for ANAMMOX reaction. The ANAMMOX reaction is fully stirred. When the ammonia nitrogen NH4 + The reaction is ended when the ammonia nitrogen NH4 -N < 10 mg / L. The reaction is ended, and the effluent is precipitated and fed into the reaction tank of the main wastewater treatment system. The effluent volume is 30-60% of the tank volume. After the effluent is completed, the next reaction cycle is started. c) Another part of the bypass short-cut nitrification tank I effluent flows into the bypass short-cut nitrification tank II for short-cut nitrification reaction, and the remaining ammonia nitrogen NH4 + - N is all converted into nitrite NO2 - - N, after the reaction, standing, precipitation, effluent to the reaction tank of the main wastewater treatment system, the effluent volume is 30-60% of the volume, and after the effluent, waiting for entering the next reaction cycle.

6. The process method of the combined process sewage treatment system according to claim 2, characterized in that: In the b) operation phase, the anaerobic ammonia oxidation AAOB bacteria cultivated in the start-up phase of the anaerobic ammonia oxidation bypass system are discharged into the anaerobic tank of the main stream treatment system with the sludge of the bypass anaerobic ammonia oxidation tank, and in the main stream treatment system, the denitrification process is gradually changed from the original single nitrification-denitrification process to the coexistence process of nitrification-denitrification, short-cut nitrification and anaerobic ammonia oxidation, and the denitrification is performed by the combined operation of the nitrification-denitrification, short-cut nitrification and anaerobic ammonia oxidation processes, and the process steps include the following: a) the mixed sewage formed by the effluent of the by-pass short-cut nitrification tank I or the by-pass short-cut nitrification tank II and the by-pass ANAMMOX tank of the sewage to be treated is introduced into the anaerobic tank of the main stream treatment system, the sludge of the by-pass ANAMMOX tank of the ANAMMOX by-pass system is discharged into the anaerobic tank of the main stream treatment system, the dissolved oxygen DO in the anaerobic tank is controlled to be less than 0.2 mg / L, so that the ANAMMOX reaction and the denitrification reaction are simultaneously carried out in the anaerobic tank, and in the ANAMMOX reaction process in the anaerobic tank, the AAOB bacteria and the denitrifying bacteria compete for the substrate to obtain the nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 + -N in the sewage is recycled, the ANAMMOX reaction is carried out, and the total nitrogen TN is removed; b) After the anaerobic tank reaction, the sludge-water mixture enters the anoxic tank, and the dissolved oxygen DO in the anoxic tank is controlled to be less than 0.3 mg / L. In the anoxic tank, the anaerobic ammonia oxidation denitrification reaction also occurs, and the anaerobic ammonia oxidation AAOB bacteria compete with the denitrifying bacteria for the substrate to obtain nitrite nitrogen NO2 - -N, the ammonia nitrogen NH4 in the sewage is recycled + -N, the anaerobic ammonia oxidation reaction is carried out to remove total nitrogen TN; c) After the reaction in the anoxic tank, the sludge-water mixture enters the low-oxygen aeration tank, and the dissolved oxygen DO in the low-oxygen aeration tank is controlled to be 0.1 to 0.5 mg / L, so that the short-cut nitrification reaction, the anaerobic ammonia oxidation reaction and the denitrification reaction are simultaneously performed in the low-oxygen aeration tank, the total nitrogen TN is removed by the combined short-cut nitrification process, anaerobic ammonia oxidation process and denitrification process in the low-oxygen aeration tank, and the sludge-water mixture in the low-oxygen aeration tank is returned to the anoxic tank with a return ratio of 30% to 100%; d) After the low-oxygen aeration tank reaction, the sludge-water mixture enters the aerobic tank, the dissolved oxygen DO in the aerobic tank is controlled to be 1-5 mg / L, so that nitrification reaction occurs in the aerobic tank to remove ammonia nitrogen NH4 + -N; the generated nitrate NO3 - -N is removed by denitrification when the sludge-water mixture is backflowed to the anoxic tank, and the backflow ratio is 50%-200%. e) The sludge-water mixture after the reaction in the aerobic tank enters the secondary sedimentation tank for sludge-water separation, the clear liquid flows out of the main stream treatment system, and the sludge is returned to the anaerobic tank with a return ratio of 30% to 100%.

7. A process method for a combined process wastewater treatment system according to any one of claims 5 or 6, characterised in that: The total hydraulic retention time of the anaerobic tank, the anoxic tank, the low-oxygen aeration tank and the aerobic tank is 9 to 14 hours, and the hydraulic retention time distribution ratio of each reaction tank is: anaerobic tank: anoxic tank: low-oxygen aeration tank: aerobic tank = (2.4 to 3.5): (2.6 to 4.5): (1 to 2.5): (3 to 3.5).

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