A method for realizing anaerobic ammonia oxidation of municipal wastewater in a coastal wastewater treatment plant

Abstract

The application discloses a method for realizing anaerobic ammonia oxidation of municipal wastewater in a coastal sewage treatment plant, wherein low-ammonia-nitrogen-concentration municipal wastewater is first subjected to a main stream nitrification reactor, nitrification sludge is subjected to preliminary solid-liquid separation and concentration in a sedimentation tank, and the concentrated nitrification sludge is introduced into an ex-situ high-salinity inhibition tank; seawater is used as an inhibitor, the concentrated nitrification sludge and seawater are mixed in the ex-situ high-salinity inhibition tank, after high-salinity inhibition, the seawater and the concentrated sludge in the ex-situ high-salinity inhibition tank are returned to a main stream short-cut nitrification reactor through a pump to realize a short-cut nitrification process; the proportion of nitrite and ammonia nitrogen in the effluent of the main stream short-cut nitrification reactor is adjusted by controlling the aeration amount, and organic matters are removed; and after the effluent enters a main stream anaerobic ammonia oxidation unit, an anaerobic ammonia oxidation denitrification process of municipal wastewater is realized. The method has the characteristics of simple regulation and control and high economic efficiency by using an ex-situ salinity strategy to inhibit nitrite oxidizing bacteria (NOB) and realizing autotrophic denitrification of municipal wastewater.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, and in particular to a method for achieving anaerobic ammonia oxidation of urban wastewater in coastal wastewater treatment plants. Background Technology

[0002] Traditional activated sludge processes and their derivative improved processes are the most widely used methods for treating municipal wastewater, especially nitrification / denitrification, which is the primary technical means. These processes are simple to operate and can remove nitrogen and phosphorus while degrading organic matter, making them the mainstream treatment process in municipal wastewater treatment plants. However, traditional activated sludge processes generally suffer from high aeration energy consumption, the need for external carbon sources, large sludge production, and high carbon emissions during nitrogen removal.

[0003] In recent years, anammox, an emerging autotrophic nitrogen removal technology, has received widespread attention since its discovery. Anammox bacteria, as autotrophic nitrogen-removing bacteria, can reduce ammonia nitrogen to nitrogen gas using nitrite nitrogen as an electron acceptor in an anaerobic environment. This process requires no aeration or organic carbon source, making it the most economical and efficient wastewater nitrogen removal technology currently available. Although anammox technology has been widely used in the treatment of high-ammonia-nitrogen wastewater such as sludge digestate, landfill leachate, aquaculture wastewater, and pharmaceutical wastewater, its large-scale application in low-ammonia-nitrogen wastewater, primarily municipal sewage, still faces several bottlenecks. Among these, since nitrogen in urban sewage mainly exists in the form of ammonia nitrogen, short-cut nitrification is an ideal process for providing a nitrite nitrogen substrate; however, stable short-cut nitrification under low-ammonia-nitrogen wastewater conditions remains a challenging problem.

[0004] The essence of achieving short-cut nitrification is to control the nitrification process of ammonia nitrogen at the nitrite stage by maintaining the activity of ammonia-oxidizing bacteria (AOB) while inhibiting nitrite-oxidizing bacteria (NOB). Currently, methods for inhibiting NOB in urban wastewater with low ammonia nitrogen concentrations mainly involve in-situ regulation. This involves controlling dissolved oxygen concentration, using intermittent aeration, and controlling the residual ammonia nitrogen concentration in the aeration tank to directly or indirectly limit the substrate from which NOB grows, thus slowing its growth rate. Alternatively, adjusting the solid-state reaction time (SRT) can allow more NOB to be washed out of the reactor. However, in mainstream low-nitrogen (NH4+) wastewater... + <50mg NL -1Under conditions of low temperature (<25℃), in-situ NOB suppression strategies still struggle to achieve long-term stable short-cut nitrification. Ex-situ NOB deactivation is another effective strategy, utilizing the differences in sensitivity of AOB and NOB to harsh environmental conditions, such as high-temperature shocks, free ammonia / free nitrite (FA / FNA), sulfides, and ultrasound, to deactivate NOB while retaining some AOB activity. The process involves first concentrating the sludge in the mainstream nitrification tank, then performing ex-situ suppression on the concentrated sludge, and finally returning the suppressed sludge to the mainstream reactor. However, current ex-situ deactivation strategies also face the problem of NOB adaptation due to NOB community replacement after long-term use, leading to the failure of the mainstream short-cut nitrification process. Furthermore, additional reagent dosage and energy input further increase costs, and the harsh suppression conditions also affect sludge properties, resulting in sludge loss upon return to the mainstream reactor. Summary of the Invention

[0005] In view of the aforementioned shortcomings of the prior art, the technical problem to be solved by the present invention is that current anaerobic ammonia oxidation methods are complex, inefficient, costly, and lack environmental friendliness. Therefore, the present invention provides a method for anaerobic ammonia oxidation of urban wastewater in coastal wastewater treatment plants. This method utilizes an ex-situ salinity strategy to suppress NOB, thereby achieving stable short-cut nitrification of low-ammonia nitrogen wastewater. It solves the problem of unstable nitrite supply in the existing anaerobic ammonia oxidation process for low-ammonia nitrogen wastewater, achieving autotrophic denitrification of urban wastewater. The method is characterized by simple control, stability, and high efficiency.

[0006] To achieve the above objectives, the present invention provides a method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant, comprising the following steps:

[0007] Urban wastewater with low ammonia nitrogen concentration first passes through the main nitrification reactor. Nitrified sludge undergoes preliminary solid-liquid separation in a sedimentation tank. A portion of the nitrified sludge from the sedimentation tank is then concentrated in a sludge thickening unit. The concentrated nitrified sludge enters an off-site high-salinity inhibition tank. A small amount of saline seawater is pumped from the ocean as an inhibitor. The concentrated nitrified sludge and seawater are mixed in the off-site high-salinity inhibition tank and allowed to settle for a period. After the high-salinity inhibition is complete, the seawater and concentrated sludge from the off-site high-salinity inhibition tank are pumped back to the main short-cut nitrification reactor, where short-cut nitrification is achieved. The ratio of nitrite to ammonia nitrogen in the effluent from the main short-cut nitrification reactor is adjusted by controlling the aeration rate to remove organic matter. The effluent then enters the main anaerobic ammonia oxidation unit to achieve anaerobic ammonia oxidation denitrification of urban wastewater.

[0008] Furthermore, the sludge and water are thoroughly mixed in the mainstream nitrification reactor, and the sludge concentration in the mainstream nitrification reactor is 0.5-4 g MLSS / L.

[0009] Furthermore, after preliminary solid-liquid separation in the sedimentation tank, the liquid phase of the nitrified sludge enters the mainstream anaerobic ammonia oxidation unit, while part of the solid sludge is returned to the mainstream nitrification reactor, with a sludge return ratio set at 30-70%. Among these, a portion of the sludge enters the sludge thickening unit for further thickening, accounting for 10-50% of the total sludge in the mainstream nitrification reactor; the remaining sludge is discharged as waste sludge.

[0010] Furthermore, the sludge thickening unit thickens the nitrified sludge to a concentration of 20-40 g MLSS / L.

[0011] Furthermore, when a small amount of salt-rich seawater is pumped from the ocean as an inhibitor, the salinity of the seawater is 3.0%-4.0%.

[0012] Furthermore, after the seawater and concentrated sludge in the ex-situ high salinity inhibition tank are mixed, the salinity of the mixture is 2.0-3.5%.

[0013] Furthermore, the ex-situ high salinity inhibition process continues for 6-24 hours within the ex-situ high salinity inhibition tank.

[0014] Furthermore, the seawater and concentrated sludge in the ex-situ high salinity inhibition tank are pumped directly back into the main short-cut nitrification reactor.

[0015] Furthermore, the mainstream nitrification reactor adjusts the ratio of nitrite to ammonia nitrogen in the effluent of the mainstream short-cut nitrification reactor by controlling the aeration rate, maintaining the nitrite:ammonia nitrogen ratio in the effluent at 1 to 1.32, while removing most of the organic matter in the influent.

[0016] Furthermore, the frequency of ex-situ high salinity suppression depends on the nitrite accumulation rate (NAR%) in the mainstream nitrification reactor: NAR% = (effluent nitrite concentration - influent nitrite concentration) / (effluent nitrite concentration + effluent nitrite-nitrogen concentration - influent nitrite concentration - influent nitrite-nitrogen concentration) × 100%. When NAR% is below 90%, high salinity suppression is carried out, with a suppression frequency of once every 1-3 days.

[0017] Technical effect

[0018] This invention provides a method for anaerobic ammonia oxidation of urban wastewater in coastal wastewater treatment plants. Urban wastewater with low ammonia nitrogen concentration first passes through a main nitrification reactor. Nitrified sludge undergoes preliminary solid-liquid separation in a sedimentation tank. A portion of the nitrified sludge from the sedimentation tank is then concentrated in a sludge thickening unit. The concentrated nitrified sludge enters an ex-situ high-salinity inhibition tank. A small amount of saline seawater is pumped from the ocean as an inhibitor. The concentrated nitrified sludge and seawater are mixed in the ex-situ high-salinity inhibition tank and allowed to stand for a period of time. During this time, taking advantage of the different sensitivities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the nitrified sludge to high salinity, NOB activity is almost completely lost after high-salinity inhibition, while AOB retains some activity. After high-salinity inhibition, the seawater and concentrated sludge in the inhibition tank are pumped back to the main short-cut nitrification reactor, where the short-cut nitrification process is realized. By controlling the aeration rate to adjust the ratio of nitrite and ammonia nitrogen in the effluent of the mainstream short-cut nitrification reactor, the effluent enters the mainstream anaerobic ammonia oxidation unit to achieve the anaerobic ammonia oxidation autotrophic denitrification process of urban sewage.

[0019] This invention achieves autotrophic denitrification of urban wastewater with low ammonia nitrogen concentrations. Excess organic matter in the wastewater can be captured and recycled through pretreatment. Addressing the challenge of stable nitrite production from low-ammonia nitrogen concentration urban wastewater using anaerobic ammonia oxidation (ANAO), this invention leverages the readily available high-salinity resources of coastal wastewater treatment plants. High-salinity seawater selectively inhibits NOB activity while retaining AOB activity, controlling the mainstream nitrification process at the nitrite stage. This provides a stable substrate for ANAO, achieving a low-carbon and energy-saving autotrophic denitrification process. Furthermore, compared to other ex-situ NOB inactivation strategies, high-salinity inhibition is simple to regulate, requiring only control of the mixing ratio of concentrated sludge and seawater; no additional chemical agents or large energy inputs are needed, saving economic costs. A small amount of high-salinity seawater entering the mainstream dilutes the salinity without interfering with the mainstream biological system. The salinity is recycled after discharge into the ocean, resulting in significant environmental and economic benefits.

[0020] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0021] Figure 1 This is a schematic flowchart of a preferred embodiment of the present invention for realizing anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant;

[0022] Figure 2This is a preferred embodiment of the present invention, which describes the retention of AOB and NOB activities under different salinity and inhibition time using an ex-situ high salinity inhibition strategy for a method of achieving anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant.

[0023] Figure 3 The nitrite accumulation in the nitrification reactor after a single treatment with an ex-situ high salinity inhibition strategy (inhibition at 35g NaCl / L for 24h) is as follows: changes in nitrite accumulation rate over 8 cycles (a); changes in trinitrogen concentration in the first cycle; and changes in trinitrogen concentration in the fourth cycle. Detailed Implementation

[0024] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0025] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will appreciate that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the invention with unnecessary detail.

[0026] like Figure 1 As shown, this invention provides a method for anaerobic ammonia oxidation of urban sewage in coastal sewage treatment plants, comprising the following steps:

[0027] Urban wastewater with low ammonia nitrogen concentration first passes through the main nitrification reactor. After preliminary solid-liquid separation in the sedimentation tank, a portion of the nitrified sludge from the sedimentation tank is collected and concentrated in the sludge thickening unit. The concentrated nitrified sludge then enters the ex-situ high salinity inhibition tank. A small amount of salt-rich seawater is pumped from the ocean as an inhibitor. The concentrated nitrified sludge and seawater are mixed in the ex-situ high salinity inhibition tank and left to stand for a period of time. During this time, taking advantage of the different sensitivities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the nitrified sludge to high salinity, NOB activity is almost lost after high salinity inhibition, while AOB retains some activity. After the high salinity inhibition is completed, the seawater and concentrated sludge in the off-site high salinity inhibition tank are returned to the mainstream short-cut nitrification reactor by a pump, where the short-cut nitrification process is realized. By controlling the aeration rate to adjust the ratio of nitrite and ammonia nitrogen in the effluent of the mainstream short-cut nitrification reactor, organic matter is removed, and the effluent enters the mainstream anaerobic ammonia oxidation unit to realize the anaerobic ammonia oxidation denitrification process of urban sewage.

[0028] Specifically, the sludge and water are thoroughly mixed in the main nitrification reactor, with a sludge concentration of 0.5-4 g MLSS / L. After initial solid-liquid separation in the sedimentation tank, the nitrified sludge from the main nitrification reactor enters the main anaerobic ammonium oxidation unit, while a portion of the solid sludge is returned to the main nitrification reactor at a sludge return ratio of 30-70%. A portion of this sludge, accounting for 10-50% of the total sludge in the main nitrification reactor, enters the sludge thickening unit for further concentration; the remaining sludge is discharged as waste sludge.

[0029] The sludge thickening unit thickens the nitrified sludge to a concentration of 20-40 g MLSS / L.

[0030] When a small amount of salt-rich seawater is pumped from the ocean as an inhibitor, the salinity of the seawater is 3.0%-4.0%.

[0031] After mixing, the seawater and concentrated sludge in the ex-situ high salinity suppression tank achieve a salinity of 2.0-3.5%. The ex-situ high salinity suppression process lasts for 6-24 hours within the tank. The seawater and concentrated sludge from the tank are then pumped directly back to the main flow short-cut nitrification reactor. The frequency of ex-situ high salinity suppression depends on the nitrite accumulation rate (NAR%) in the main flow nitrification reactor: NAR% = (effluent nitrite concentration - influent nitrite concentration) / (effluent nitrite concentration + effluent nitrate nitrogen concentration - influent nitrite concentration - influent nitrate nitrogen concentration). High salinity suppression is initiated when NAR% is below 90%, with a suppression frequency of once every 1-3 days.

[0032] The mainstream nitrification reactor adjusts the ratio of nitrite to ammonia nitrogen in the effluent of the mainstream short-cut nitrification reactor by controlling the aeration rate, maintaining the nitrite:ammonia nitrogen ratio at 1 to 1.32, while removing most of the organic matter in the influent.

[0033] Example 1

[0034] In this embodiment, the sludge concentration in the reactor is 2.0 g MLSS / L. The sedimentation tank has good solid-liquid separation capability. The liquid phase enters the downstream mainstream anaerobic ammonia oxidation unit, while part of the solid sludge is recycled to the mainstream nitrification reactor at a sludge recycling ratio of 50%. A portion of the sludge enters the sludge thickening unit for further concentration, accounting for 40% of the total sludge in the mainstream nitrification reactor. The remaining sludge is discharged as waste sludge. The sludge concentration after thickening the nitrified sludge in the sludge thickening unit can reach 30 g MLSS / L. The seawater salinity is 3.5%. The mixing conditions in the ex-situ high salinity suppression tank are good. After mixing the concentrated nitrified sludge and seawater, the salinity of the resulting mixture is 2.0%. The high salinity suppression process continues for 24 hours in the ex-situ high salinity suppression tank. Figure 2As shown, after nitrifying sludge was inhibited for 24 hours under salinity conditions of 20 g NaCl / L, the AOB activity retained 61.77% of the initial activity before inhibition, and the NOB activity retained 24.50% of the initial activity before inhibition. The NOB activity was inhibited more, and repeated inhibition operations increased the nitrite accumulation rate of the mainstream nitrification reactor.

[0035] Seawater and concentrated sludge in the suppression tank are pumped directly back to the main nitrification reactor. In the main nitrification reactor, the nitrite:ammonia nitrogen ratio in the effluent is maintained at 1.32 by controlling the aeration rate, while most of the organic matter in the influent is removed. The frequency of ex-situ high salinity suppression depends on the nitrite accumulation rate (NAR%) in the main nitrification reactor (NAR%) = (effluent nitrite concentration - influent nitrite concentration) / (effluent nitrite concentration + effluent nitrite nitrogen concentration - influent nitrite concentration - influent nitrite nitrogen concentration) × 100%). High salinity suppression is performed when the NAR is below 90%, with a suppression frequency of once a day.

[0036] Example 2

[0037] In this embodiment, the sludge concentration in the reactor is 2.0 g MLSS / L. The sedimentation tank has good solid-liquid separation capability. The liquid phase enters the downstream mainstream anaerobic ammonia oxidation unit, while part of the solid sludge is recycled to the mainstream nitrification reactor at a sludge recycling ratio of 50%. A portion of the sludge enters the sludge thickening unit for further concentration, accounting for 25% of the total sludge in the mainstream nitrification reactor. The remaining sludge is discharged as waste sludge. The sludge concentration after thickening the nitrified sludge in the sludge thickening unit can reach 30 g MLSS / L. The seawater salinity is 4%. The mixing conditions in the ex-situ high salinity suppression tank are good. After mixing the concentrated nitrified sludge and seawater, the salinity of the resulting mixture is 3.5%. The high salinity suppression process continues for 24 hours in the ex-situ high salinity suppression tank. Figure 2 As shown, after nitrifying sludge was inhibited for 24 hours under a salinity of 35 g NaCl / L, the AOB activity retained 36.65% of the initial activity before inhibition, and the NOB activity retained 7.15% of the initial activity before inhibition, indicating that the NOB activity was inhibited more significantly.

[0038] like Figure 3As shown, after nitrifying sludge was inhibited for 24 hours at a salinity of 35 g NaCl / L, the activity recovery of AOB and NOB in the mainstream nitrification reactor was simulated in an SBR reactor under conditions of influent ammonia nitrogen concentration of 50 mg N / L, nitrite concentration of 20 mg N / L, and sufficient aeration (DO > 5 mg / L). Each cycle was 6 hours, including 10 minutes of feeding, 5 hours of aerobic aeration, 40 minutes of settling, and 10 minutes of effluent discharge, with a volume exchange ratio of 40% and an HRT of 15 hours. The results showed that after only one high-salinity inhibition, a stable nitrite accumulation process occurred within 8 cycles. This process indicates that high-salinity inhibition has a stronger deactivation effect on NOB, and the inhibition effect is not immediately relieved. By controlling an appropriate inhibition frequency, a short-cut nitrification process in the mainstream nitrification reactor can be achieved after several cycles.

[0039] Seawater and concentrated sludge in the suppression tank are pumped directly back to the main nitrification reactor. In the main nitrification reactor, the nitrite:ammonia nitrogen ratio in the effluent is maintained at 1.32 by controlling the aeration rate, while simultaneously removing most of the organic matter from the influent. The frequency of ex-situ high salinity suppression depends on the nitrite accumulation rate (NAR%) in the main nitrification reactor: NAR% = (effluent nitrite concentration - influent nitrite concentration) / (effluent nitrite concentration + effluent nitrate nitrogen concentration - influent nitrite concentration - influent nitrate nitrogen concentration). High salinity suppression is performed once a day when the NAR is below 90%.

[0040] In this embodiment of the invention, autotrophic denitrification of urban wastewater with low ammonia nitrogen concentration is achieved. Excess organic matter in the wastewater can be captured and recycled through pretreatment processes. Addressing the challenge of reliably obtaining nitrite from low-ammonia nitrogen concentration urban wastewater using anaerobic ammonia oxidation, this invention fully leverages the locational advantage of readily available high-salinity resources at coastal wastewater treatment plants. High-salinity seawater selectively inhibits NOB activity while retaining AOB activity, controlling the mainstream nitrification process at the nitrite stage. This provides a stable substrate for the anaerobic ammonia oxidation process, achieving a low-carbon and energy-saving autotrophic denitrification process. Furthermore, compared to other ex-situ NOB inactivation strategies, high-salinity inhibition is simple to regulate, requiring only control of the mixing ratio of concentrated sludge and seawater; no additional chemical agents or large energy input are needed, saving economic costs. A small amount of high-salinity seawater entering the mainstream is diluted, without interfering with the mainstream biological system. The salinity is recycled after being discharged into the ocean with the effluent, resulting in significant environmental and economic benefits.

[0041] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for achieving anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant, characterized in that, Includes the following steps: Urban wastewater with low ammonia nitrogen concentration first passes through a mainstream nitrification reactor. After preliminary solid-liquid separation in a sedimentation tank, a portion of the nitrified sludge is collected and concentrated in a sludge thickening unit. The concentrated nitrified sludge then enters an off-site high-salinity inhibition tank. A small amount of saline seawater is pumped from the ocean as an inhibitor. The concentrated nitrified sludge and seawater are mixed in the off-site high-salinity inhibition tank and allowed to settle for a period of time. After the high-salinity inhibition is complete, the seawater and concentrated sludge in the off-site high-salinity inhibition tank are pumped back to the mainstream short-cut nitrification reactor, where short-cut nitrification is achieved. The ratio of nitrite to ammonia nitrogen in the effluent from the mainstream short-cut nitrification reactor is adjusted by controlling the aeration rate to remove organic matter. The effluent then enters the mainstream anaerobic ammonia oxidation unit to achieve anaerobic ammonia oxidation denitrification of urban wastewater. The sludge and water are thoroughly mixed in the mainstream nitrification reactor, and the sludge concentration in the mainstream nitrification reactor is 0.5-4g. MLSS / L; When a small amount of salt-rich seawater is pumped from the ocean as an inhibitor, the salinity of the seawater is 3.0%-4.0%; The frequency of ex-situ high salinity inhibition depends on the nitrite accumulation rate (NAR%) in the main nitrification reactor = (effluent nitrite concentration - influent nitrite concentration) / (effluent nitrite concentration + effluent nitrate nitrogen concentration - influent nitrite concentration - influent nitrate nitrogen concentration) × 100%. When NAR% is below 90%, high salinity inhibition is carried out once a day.

2. The method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 1, characterized in that, After initial solid-liquid separation in the sedimentation tank, the liquid phase of the nitrified sludge enters the mainstream anaerobic ammonia oxidation unit, while a portion of the solid sludge is returned to the mainstream nitrification reactor, with a sludge return ratio set at 30-70%. A portion of the sludge enters the sludge thickening unit for further thickening, accounting for 10-50% of the total sludge in the mainstream nitrification reactor. The remaining sludge is discharged as waste sludge.

3. The method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 2, characterized in that, The sludge thickening unit achieves a sludge concentration of 20-40 g MLSS / L after thickening the nitrified sludge.

4. The method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 3, characterized in that, The seawater and concentrated sludge in the ex-situ high salinity inhibition tank are mixed, and the salinity of the mixture is 2.0-3.5%.

5. The method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 4, characterized in that, The ex-situ high salinity inhibition process lasts for 6-24 hours in the ex-situ high salinity inhibition tank.

6. The method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 5, characterized in that, Seawater and concentrated sludge in the ex-situ high salinity inhibition tank are pumped directly back into the mainstream short-cut nitrification reactor.

7. A method for anaerobic ammonia oxidation of urban sewage in a coastal sewage treatment plant as described in claim 6, characterized in that, The mainstream nitrification reactor adjusts the ratio of nitrite to ammonia nitrogen in the effluent of the mainstream short-cut nitrification reactor by controlling the aeration rate, maintaining the nitrite:ammonia nitrogen ratio in the effluent at 1 to 1.32, while removing most of the organic matter in the influent.

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