Method for efficiently treating low-carbon-nitrogen-ratio nitrogen-containing wastewater by using chlorella and anaerobic ammonia oxidation bacteria in cooperation

Abstract

The application provides a method for efficiently treating low-carbon-nitrogen-ratio nitrogen-containing wastewater by using ball algae and anaerobic ammonia oxidation bacteria, and the method comprises the following steps: after inoculating sludge, inert gas is introduced to form a biofilm, then nitrogen-containing wastewater containing ammonia nitrogen and nitrite nitrogen is input to start up, and the integrated submerged biofilter is subjected to intermittent light treatment and light-avoiding treatment. When the sludge of a specific microbial community is produced, the sludge is run, and the microorganisms in the sludge are mainly anaerobic ammonia oxidation bacteria, the inner wall of the reactor is attached with abundant ball algae, and the integrated submerged biofilter is used to produce a reaction of ball algae and anaerobic ammonia oxidation bacteria for cooperatively treating nitrogen-containing wastewater, and the effective treatment of ammonia nitrogen and nitrite nitrogen in the integrated submerged biofilter is realized, the start-up time is short, and the integrated submerged biofilter can be stably run for more than 400 days. During the stable running period, the average removal rate of ammonia nitrogen is increased to 95.0%, the average removal rate of nitrite nitrogen is increased to 97.9%, and the average removal rate of total nitrogen is increased to 88.1%.

Description

Technical Field

[0001] This invention relates to the field of nitrogen-containing wastewater treatment, specifically to a method for the efficient treatment of nitrogen-containing wastewater with a low carbon-to-nitrogen ratio by synergistic interaction between algae and anaerobic ammonia-oxidizing bacteria. Background Technology

[0002] The pharmaceutical, chemical, fertilizer, petrochemical, coking, smelting, and slaughtering industries are major contributors to nitrogen-containing wastewater discharge in my country. This wastewater is characterized by a low C / N ratio, making it one of the more difficult types of industrial wastewater to treat. Traditional nitrification-denitrification biological denitrification technologies often encounter technical challenges such as limited biological denitrification capacity, high sludge production, large organic carbon source dosages, and high aeration volumes. Simultaneously, sludge treatment costs, reagent costs, and energy consumption also increase significantly. Therefore, selecting a suitable biological treatment process for this type of nitrogen-containing wastewater is crucial.

[0003] Anaerobic ammonia oxidation (AAO) technology, as a novel biological nitrogen removal technology, has advantages over traditional nitrification-denitrification technologies, including a shorter process flow, no consumption of organic carbon sources, and lower energy consumption (as shown in Table 1). This process offers significant technical advantages in treating wastewater with medium to high concentrations of ammonia nitrogen and low C / N ratios. However, in practical research and development, AAO technology suffers from long start-up periods and unstable operation, limiting its biological nitrogen removal capacity and impacting its applicability and application.

[0004] Table 1 Comparative Analysis of Anaerobic Ammonium Oxidation Technology and Traditional Nitrification-Denitrification Technology

[0005]

[0006] Anaerobic ammonia oxidation technology and traditional nitrification-denitrification technology have their own characteristics in treating nitrogen-containing wastewater. Currently, there is no single-stage denitrification method that can simultaneously and efficiently treat ammonia nitrogen and nitrite nitrogen wastewater. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a method for the efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic interaction between Chlorella and anaerobic ammonia-oxidizing bacteria.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for the efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic interaction between *Chlorella vulgaris* and anaerobic ammonia-oxidizing bacteria, the method comprising the following steps:

[0009] (1) Inoculate activated sludge into an integrated submerged biological filter and introduce inert gas into the integrated submerged biological filter to carry out biofilm formation.

[0010] (2) The integrated submerged biological filter is subjected to intermittent light treatment and light avoidance treatment. The ratio of the duration of the light treatment cycle to the duration of the light avoidance treatment cycle is (0.5~1.2):1. The duration of a continuous light treatment cycle is 8~15 hours. Simulated nitrogen-containing wastewater is introduced into the integrated submerged biological filter after step (1). The simulated nitrogen-containing wastewater meets the following parameters: pH 7.13~7.99, CODcr 0.0~6.0mg / L, NH4+-N 78.0~111.0mg / L, NO2--N 52.7~109.1mg / L, NO3--N 0.35~1.95mg / L. The temperature of the reaction system is controlled at 30.3~32.0℃, and the DO of the reaction system is kept at 0.

[0011] (3) Continue to input the simulated nitrogen-containing wastewater in the same batch as in step (2). When algae grow and attach to 15% to 20% of the inner wall of the integrated submerged biological filter reactor, and the microbial community meets the following conditions, the system will start successfully.

[0012] The microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms with relative abundance: Planctomycetes (50.92%–53.00%), Chloroflexi (19.32%–20.11%), Proteobacteria (11.11%–11.57%), Bactcroidetes (10.46%–10.89%), Armatimonadetes (2.81%–2.93%), and Gemmatimonadetes (1.85%–1.93%).

[0013] (4) Input the ammonia-containing wastewater to be treated into the integrated submerged biological filter and operate it stably. The ammonia-nitrogen wastewater contains ammonia nitrogen and nitrite nitrogen.

[0014] The above-mentioned method for efficiently treating nitrogen-containing wastewater with a low C / N ratio using *Chlorella* synergistically with anaerobic ammonia-oxidizing bacteria involves inoculating sludge with an inert gas biofilm, while simultaneously subjecting the integrated submerged biological filter to intermittent light and dark treatment. The filter is then started by introducing nitrogen-containing wastewater containing both ammonia nitrogen and nitrite nitrogen. When *Chlorella* grows and attaches to 15%–20% of the reactor's inner wall area, sludge with a specific microbial community is generated. After operation, the sludge contains the following microorganisms with relative abundance: *Planctomycetes* (50.92%–53.00%), *Chloroflexi* (19.32%–20.11%), *Proteobacteria* (11.11%–11.57%), and *Bacteroidetes* (…). The relative abundances of *Cyclocarya* (s) were 10.46%–10.89%, those of *Armatimonadetes* were 2.81%–2.93%, and those of *Gemmatimonadetes* were 1.85%–1.93%. This integrated submerged biofilter allows for the synergistic treatment of nitrogenous wastewater by *Cyclocarya* and anaerobic ammonia-oxidizing bacteria, simultaneously achieving effective treatment of ammonia and nitrite nitrogen in the integrated submerged biofilter. It features a short start-up time and stable operation for over 400 days. During the stable operation period, the average removal rate of ammonia nitrogen increased to 95.0%, the average removal rate of nitrite nitrogen increased to 97.9%, and the average removal rate of total nitrogen increased to 88.1%.

[0015] Preferably, in step (4), the concentration of ammonia nitrogen in the ammonia nitrogen wastewater to be treated is 78.0 to 318.3 mg / L, and the concentration of nitrite nitrogen in the ammonia nitrogen wastewater to be treated is 52.7 to 348.9 mg / L.

[0016] The above-mentioned method for the efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic interaction between Chlorella and anaerobic ammonia-oxidizing bacteria can effectively treat ammonia nitrogen with a concentration of 78.0–318.3 mg / L and nitrite nitrogen with a concentration of 52.7–348.9 mg / L in an integrated submerged biological filter.

[0017] Preferably, the system is successfully started when algae grow and attach to 15% to 20% of the inner wall of the integrated submerged biological filter reactor, and the microbial community meets the following conditions;

[0018] The microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms with relative abundance: Planctomycetes (51.96%), Chloroflexi (19.72%), Proteobacteria (11.34%), Bacteroidetes (10.68%), Armatimonadetes (2.87%), and Gemmatimonadetes (1.89%).

[0019] After the system started successfully, the ammonia nitrogen removal rate exceeded 80.0%, the nitrite nitrogen removal rate exceeded 90.0%, and the total nitrogen removal rate exceeded 75.0%.

[0020] Preferably, in step (1), the MLSS concentration of the sludge is 6500-8500 mg / L and the pH of the sludge is 6.0-9.0.

[0021] Preferably, in step (1), inert gas is introduced to control the gas pressure in the integrated submerged biological filter at 0.15-0.20 MPa, the continuous aeration time is 30-60 h, and the filter is left to stand for 10-20 min after aeration.

[0022] Preferably, in step (4), the DO in the reaction system is controlled to be 0, the pH to be 5.57 to 9.97, and the water temperature to be 26.5 to 32.6℃.

[0023] Preferably, the integrated submerged biological filter is equipped with a combined packing material, which consists of three parts: a packing disc, a plastic sleeve, and a central copper wire tube. The structure of the combined packing material is to press the plastic disc into a double-ring large plastic ring, and press the polyester filaments on the ring of the double-ring large plastic ring to make the fiber bundles evenly distributed; the inner ring of the double-ring large plastic ring is a snowflake-shaped plastic branch.

[0024] The combined packing material set in the above method consists of three parts: a single packing disc, a plastic sleeve, and a central copper wire tube. Its structure is that the plastic disc is pressed into a double-ring large plastic ring, and polyester filaments are pressed on the ring to make the fiber bundles evenly distributed. The inner ring is made of snowflake-shaped plastic branches, which can not only support the biofilm but also effectively cut air bubbles, improve the oxygen transfer rate and utilization rate, so that the water-air biofilm can be fully exchanged, and the nitrogen in the water can be treated efficiently.

[0025] Preferably, the hydraulic residence time in step (2) is 14 to 18 hours, the hydraulic residence time in step (3) is 14 to 18 hours, and the hydraulic residence time in step (4) is 14 to 18 hours.

[0026] Preferably, in step (2), bottom sediment is not discharged; in step (3), bottom sediment is not discharged; and in step (4), bottom sediment is not discharged.

[0027] Preferably, in step (1), the ratio of the amount of biofilm activated sludge used to the effective volume of the integrated submerged biological filter is (0.8-1.0):1.

[0028] The beneficial effects of this invention are as follows: This invention provides a method for the efficient treatment of nitrogen-containing wastewater with a low carbon-to-nitrogen ratio using *Chlorella vulgaris* in synergy with anaerobic ammonia-oxidizing bacteria. The method involves introducing an inert gas to allow biofilm formation after sludge inoculation, while simultaneously subjecting an integrated submerged biological filter to intermittent light and light-shielding treatments. Then, the system is started by introducing nitrogen-containing wastewater containing both ammonia nitrogen and nitrite nitrogen. When algae grow and attach to 15%–20% of the reactor's inner wall area, sludge containing a specific microbial community is generated. After operation, the sludge contains the following microorganisms in relative abundance: Planctomycetes (50.92%–53.00%), Chloroflexi (19.32%–20.11%), Proteobacteria (11.11%–11.57%), and Bacteroidetes (10.46%–10.89%). The relative abundance of Armatimonadetes is 2.81%–2.93%, and the relative abundance of Gemmatimonadetes is 1.85%–1.93%. This allows for the synergistic treatment of nitrogenous wastewater by *Chlorella* and anaerobic ammonia-oxidizing bacteria within the same integrated submerged biological filter. Simultaneously, it achieves effective treatment of ammonia nitrogen and nitrite nitrogen in the integrated submerged biological filter, increasing the average removal rate of ammonia nitrogen to 95.0%, nitrite nitrogen to 97.9%, and total nitrogen to 88.1%, demonstrating significant technical advantages.

[0029] The technology of this invention differs from conventional technology in the following ways and has the following advantages:

[0030] (1) Effective synergistic combination of Chlorella and anaerobic ammonia-oxidizing bacteria. Conventional anaerobic ammonia oxidation technology mainly relies on anaerobic ammonia-oxidizing bacteria to complete the biological denitrification of wastewater, and the contributors are relatively singular. The technology of this invention enriches anaerobic ammonia-oxidizing bacteria on biological packing material, and Chlorella grows and accumulates on the inner wall of the reactor, realizing an effective synergistic combination of Chlorella and anaerobic ammonia-oxidizing bacteria, and efficiently removing nitrogen from wastewater. This has significant technological breakthrough advantages.

[0031] (2) Enriching and Enhancing Biological Denitrification Treatment Pathways. Conventional anaerobic ammonia oxidation technology mainly relies on anaerobic ammonia-oxidizing bacteria to react ammonia nitrogen and nitrite nitrogen to generate a large amount of nitrogen gas and a small amount of nitrate nitrogen, thereby effectively removing nitrogen from wastewater. This invention, while employing the above biological denitrification pathways, utilizes Chlorella to absorb ammonia nitrogen and nitrite through photosynthesis, further effectively treating nitrogen-containing wastewater and enriching and enhancing biological denitrification treatment pathways.

[0032] (3) Effectively improves biological nitrogen removal performance. Conventional anaerobic ammonia oxidation technology achieves an average ammonia nitrogen removal rate of 80% and an average total nitrogen removal rate of 70% during operation. The technology of this invention combines algae with anaerobic ammonia oxidation technology, increasing the average ammonia nitrogen removal rate to 95.0%, the average nitrite nitrogen removal rate to 97.9%, and the average total nitrogen removal rate to 88.1%, demonstrating significant technical advantages.

[0033] (4) Further improve the stability of system operation. Conventional anaerobic ammonia oxidation technology is very sensitive to changes in parameters such as temperature, dissolved oxygen, pH, influent ammonia nitrogen load, and hydraulic retention time during operation. To ensure stable operation, these parameters need to be strictly controlled within a small threshold range. The technology of this invention, during startup and operation, exhibits a wider pH range and a wider temperature range within the reaction system compared to conventional methods, while also shortening the hydraulic retention time. This demonstrates significant advantages in the engineering application of the technology. Simultaneously, Chlorella releases a small amount of oxygen during photosynthesis, which does not affect the activity of anaerobic ammonia oxidizing bacteria. Furthermore, Chlorella can inhibit cyanobacteria and provide some system insulation, further promoting the activity and stability of sludge microorganisms. Therefore, the ammonia nitrogen and total nitrogen removal rates of this invention are significantly higher than conventional methods, and it has operated stably for over 400 days, fully demonstrating the improved operational stability of the technology. Attached Figure Description

[0034] Figure 1 This invention illustrates the distribution of microbial communities in the activated sludge of an integrated submerged biological filter in a method for the efficient treatment of nitrogen-containing wastewater with a low carbon-to-nitrogen ratio using algae in synergy with anaerobic ammonia-oxidizing bacteria.

[0035] Figure 2 This is an analysis diagram of algae in the activated sludge of an integrated submerged biological filter in the method for efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic interaction of *Chlorella vulgaris* and anaerobic ammonia-oxidizing bacteria in an embodiment of the present invention.

[0036] Figure 3 The figure shows the operational results of the method for efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic use of *Chlorella vulgaris* and anaerobic ammonia-oxidizing bacteria according to an embodiment of the present invention.

[0037] Figure 4The figure shows the operational results of the method for efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic use of *Chlorella vulgaris* and anaerobic ammonia-oxidizing bacteria according to an embodiment of the present invention. Detailed Implementation

[0038] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0039] Example 1

[0040] As an embodiment of the present invention, a method for efficiently treating nitrogen-containing wastewater with a low carbon-to-nitrogen ratio using *Chlorella vulgaris* synergistically with anaerobic ammonia-oxidizing bacteria includes the following steps:

[0041] (1) Activated sludge is inoculated into an integrated submerged biological filter, and inert gas is introduced into the integrated submerged biological filter for biofilm formation; the MLSS concentration of the sludge is 7500 mg / L, the pH of the sludge is 7.5, and inert gas is introduced to control the gas pressure in the integrated submerged biological filter at 0.15-0.20 MPa, the continuous aeration time is 40 h, and the filter is allowed to stand for 15 min after aeration. The integrated submerged biological filter is equipped with a combined packing material, which consists of a packing sheet, a plastic sleeve, and a central copper wire. The structure of the combined packing material is to press the plastic disc into a double-ring large plastic ring, and press the polyester filaments on the ring of the double-ring large plastic ring to make the fiber bundles evenly distributed. The inner ring of the double-ring large plastic ring is a snowflake-shaped plastic branch. The ratio of the amount of activated sludge used for biofilm formation to the effective volume of the integrated submerged biological filter is 0.8:1.

[0042] (2) The integrated submerged biological filter is subjected to intermittent light treatment and light avoidance treatment. The ratio of the duration of the light treatment cycle to the light avoidance treatment cycle is 10:14, and the duration of a continuous light treatment cycle is 10 hours. Simulated nitrogen-containing wastewater is introduced into the integrated submerged biological filter after step (1). The simulated nitrogen-containing wastewater meets the following parameters: pH 7.13~7.99, CODcr 0.0~6.0mg / L, NH4+-N 78.0~111.0mg / L, NO2--N 52.7~109.0mg / L, NO3--N 0.35~1.95mg / L. The temperature of the reaction system is controlled at 30.3~32.0℃, and the DO of the reaction system is kept at 0. The hydraulic retention time is 15 hours, and the bottom sludge is not discharged.

[0043] (3) Continue to input the simulated nitrogen-containing wastewater in the same batch as in step (2). When algae grow and attach to 15% of the inner wall of the reactor in the integrated submerged biological filter, and the microbial community meets the following conditions, the activated sludge turns red, and the system starts successfully; the hydraulic retention time is 15 hours, and the bottom sludge is not discharged.

[0044] The microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms with relative abundance: Planctomycetes (51.96%), Chloroflexi (19.72%), Proteobacteria (11.34%), Bacteroidetes (10.68%), Armatimonadetes (2.87%), and Gemmatimonadetes (1.89%).

[0045] (4) Input the nitrogen-containing wastewater to be treated into the integrated submerged biological filter, control the DO in the reaction system to be 0, the pH to be 5.57 to 9.97, the water temperature to be 26.5 to 32.6℃, and operate stably. The nitrogen-containing wastewater to be treated contains ammonia nitrogen and nitrite nitrogen. The concentration of ammonia nitrogen in the nitrogen-containing wastewater to be treated is 94.5 to 318.3 mg / L, and the concentration of nitrite nitrogen in the nitrogen-containing wastewater to be treated is 90.1 to 348.9 mg / L.

[0046] I. Experimental Methods

[0047] (I) Experimental Materials

[0048] 1. The simulated nitrogen-containing water quality parameters are as follows: pH 7.13-7.99, CODcr 0.0-6.0mg / L, NH4+-N 78.0-111.0mg / L, NO2--N 52.7-109.0mg / L, NO3--N 0.35-1.95mg / L.

[0049] 2. Preparation of activated sludge. Ordinary activated sludge from the secondary sedimentation tank of a municipal wastewater treatment plant was used as activated sludge. The sludge was light yellowish-brown in color, with a pH of 7.5 and a MLSS of 2500 mg / L. After 0.5 hours of sedimentation, the sludge concentration MLSS was 7500 mg / L.

[0050] (II) Simulation Experiment of a Method for Highly Efficient Treatment of Low-Carbon Nitrogen-Containing Wastewater by Chlorella Synergistic with Anaerobic Ammonia-Oxidizing Bacteria

[0051] (1) Take 2.8L of sludge with a pH of 7.5 and a MLSS concentration of 7500mg / L and add it to an integrated submerged biological filter (SBAF) reactor. The integrated submerged biological filter is equipped with a combined packing material, which consists of three parts: a packing disc, a plastic sleeve, and a central copper wire tube. The structure of the combined packing material is to press the plastic disc into a double-ring large plastic ring, and press polyester filaments onto the rings of the double-ring large plastic ring to make the fiber bundles evenly distributed. The inner ring of the double-ring large plastic ring is a snowflake-shaped plastic branch. The effective volume of the submerged biological filter (SBAF) is 3.2L. Pure nitrogen gas is introduced into the bottom of the SBAF reactor at a pressure controlled within the range of 0.18-0.20 MPa for 40 hours to allow for biofilm formation. The actual ratio of sludge volume used for biofilm formation to the effective volume of the reactor is 1:2. During the biofilm formation process, the sludge in the SBAF reactor gradually adheres to the surface of the combined packing material, and the sludge color changes from light yellowish-brown to dark brown. After stopping the nitrogen supply and allowing it to stand for 20 minutes, the remaining sludge is discharged from the sludge discharge port at the bottom of the reactor.

[0052] (2) The integrated submerged biological filter was subjected to intermittent light and dark treatments. The ratio of the light treatment cycle to the dark treatment cycle was 10:14, and the duration of one continuous light treatment cycle was 10 hours. A peristaltic pump was used to input the simulated ammonia nitrogen wastewater into the SBAF reactor in step (1) where the biofilm had successfully attached. The simulated ammonia nitrogen wastewater met the following parameters: pH 7.13-7.99, CODcr 0.0-6.0 mg / L, NH4+-N 78.0-111.0 mg / L, NO2--N 52.7-109.0 mg / L, NO3--N 0.35-1.95 mg / L, temperature 30.3~32.0℃, and the DO of the reaction system was kept at 0. The hydraulic retention time was 15 hours, and no bottom sludge was discharged. No aeration was performed throughout the process. The start-up results are shown in [link to start-up results]. Figure 3 , Figure 4 .

[0053] like Figure 3 , Figure 4As shown, the above process lasted for 32 days. From day 1 to day 7, the sludge was in the initial inoculation stage. The anaerobic environment severely inhibited the activity of aerobic ammonia-oxidizing bacteria and nitrifying bacteria, resulting in only a portion of NH4+-N being oxidized. The effluent NH4+-N concentration ranged from 15.0 to 33.0 mg / L; the effluent NO2--N concentration gradually increased from 0.0 mg / L to 25.7 mg / L; and the effluent NO3--N concentration ranged from 16.9 to 21.0 mg / L. During days 8-32, a large amount of anaerobic ammonia-oxidizing bacteria began to accumulate in the system, causing a gradual decrease in effluent NH4+-N concentration, ranging from 3.0 to 42.0 mg / L with an average concentration of 15.6 mg / L; effluent NO2--N concentration ranged from 1.0 to 23.5 mg / L with an average concentration of 10.3 mg / L; and effluent NO3--N concentration ranged from 15.4 to 21.0 mg / L with an average concentration of 17.9 mg / L. This indicates that nitrifying bacteria were effectively inhibited. At this time, the average ammonia nitrogen conversion rate increased from 62.2% to 100.0%, the nitrite nitrogen removal rate ranged from 90.9% to 100.0%, and the total nitrogen removal rate increased from 44.4% to 86.9%, achieving successful start-up of the Chlorella-co-synergistic anaerobic ammonia oxidation process. Furthermore, during the start-up period, no organic carbon source was added, and the reactor operated continuously and stably without sludge discharge.

[0054] (3) Continue to input the simulated ammonia nitrogen wastewater described in step (2) in multiple batches, with a hydraulic retention time of 15 hours, and do not discharge bottom sludge; when algae grow and attach to 15% of the inner wall of the reactor, and the microbial community meets the following conditions, the activated sludge turns red, and the system starts successfully; the microbial community in the activated sludge of the integrated submerged biological filter includes the following microorganisms with relative abundance: the relative abundance of Planctomycetes is 51.96%, and the relative abundance of Chloroformis is 51.96%. The relative abundance of *Flexi* was 19.72%, *Proteobacteria* was 11.34%, *Bacteroidetes* was 10.68%, *Armatimonadetes* was 2.87%, and *Gemmatimonadetes* was 1.89%. The distribution of the microbial community in the activated sludge of the integrated submerged biological filter is as follows: Figure 1 As shown, the algae analysis in the reaction system at this time is as follows: Figure 2 As shown.

[0055] (4) Input the nitrogen-containing wastewater to be treated into the integrated submerged biological filter. For simulation purposes, the nitrogen-containing wastewater to be treated in this step should be replaced by artificially simulated nitrogen-containing wastewater. The nitrogen-containing wastewater meets the following parameters: pH 6.91~8.84, CODcr 0.0~9.0mg / L, NH4+-N 94.5~318.3mg / L, NO2--N 90.1~348.9mg / L, NO3--N 0.1~1.8mg / L. Control the DO in the reaction system to 0, pH to 5.57~9.97, and water temperature to 26.5~32.6℃, and ensure stable operation. The results of stable operation are shown in […]. Figure 3 , Figure 4 .

[0056] like Figure 3 , Figure 4 As shown, after the system entered the operational phase, from day 33 to 440, the influent NH4+-N concentration increased from 94.5 mg / L to 318.3 mg / L, and the influent NO2--N concentration increased from 90.1 mg / L to 348.9 mg / L. The effluent NH4+-N concentration ranged from 0.0 to 34.7 mg / L, with an average concentration of 8.4 mg / L; the effluent NO2--N concentration ranged from 0.0 to 14.0 mg / L, with an average concentration of 3.5 mg / L. Both effluent NH4+-N and NO2--N concentrations remained consistently low. The effluent NO3--N concentration ranged from 10.5 to 20.2 mg / L, with an average concentration of 17.2 mg / L, indicating extremely low nitrifying bacteria content in the system. During this operational phase, the ammonia nitrogen removal rate ranged from 82.5% to 100.0%, with an average removal rate of 95.0%; the nitrite nitrogen removal rate ranged from 90.9% to 100.0%, with an average removal rate of 97.9%; and the total nitrogen removal rate ranged from 76.8% to 95.7%, with an average removal rate of 88.1%. Simultaneously, no organic carbon source was added to the reaction system throughout the entire operation period, and the reactor operated continuously and stably without sludge discharge.

[0057] In the simulation experiment of the above-mentioned method for efficient treatment of nitrogen-containing wastewater with low carbon-to-nitrogen ratio by synergistic anaerobic ammonia-oxidizing bacteria, the influent and effluent water quality and effluent technical parameters are shown in Tables 2, 3 and 4, respectively.

[0058] Table 2. Influent and Effluent Water Quality and Reaction System Parameters of the Invention (Days 1-32, System Startup) Key Influent and Effluent Water Quality Parameters

[0059]

[0060] Table 3. Influent and effluent water quality and reaction system parameters of the present invention (d. 33-440, during stable operation).

[0061]

[0062] Table 4 Comparison of Parameters

[0063]

[0064] From Tables 2-4, Figure 3 , Figure 4 It is known that the reaction of algae and anaerobic ammonia-oxidizing bacteria in the synergistic treatment of nitrogen-containing wastewater can be carried out in the same integrated submerged biological filter, and the ammonia nitrogen and nitrite nitrogen in the integrated submerged biological filter can be effectively treated at the same time. It has a short start-up time and can operate stably for more than 400 days. The average removal rate of ammonia nitrogen is increased to 95.0%, the average removal rate of nitrite nitrogen is increased to 97.9%, and the average removal rate of total nitrogen is increased to 88.1%.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for efficient treatment of low carbon to nitrogen ratio nitrogen-containing wastewater by a combination of a ball algae and anammox bacteria, characterized in that, The method comprises the following steps: (1) inoculating activated sludge into an integrated submerged biofilter, and introducing inert gas into the integrated submerged biofilter to carry out biological membrane formation; (2) performing intermittent light treatment and light-avoiding treatment on the integrated submerged biofilter, the length ratio of a light treatment period to a light-avoiding treatment period is (0.5-1.2):1, and a length of one continuous light treatment period is 8-15 hours; inputting simulated nitrogen-containing wastewater into the integrated submerged biofilter after the treatment in step (1), wherein the simulated nitrogen-containing wastewater meets the following parameters: pH 7.13-7.99, CODcr 0.0-6.0 mg / L, NH4 + -N 78.0-111.0 mg / L, NO2 - -N 52.7-109.1 mg / L, NO3 - -N 0.35-1.95 mg / L, controlling a temperature of the reaction system to be 30.3-32.0 DEG C, and keeping DO of the reaction system to be 0; (3) continuing to input the same simulated nitrogen-containing wastewater as in step (2) in multiple batches, and when 15% to 20% of the area of the reactor inner wall of the integrated submerged biofilter is grown and attached with Chlorella, and the microbial community meets the following conditions, the system is successfully started; The microbial community in the activated sludge in the integrated submerged biofilter comprises the following microorganisms with the following relative abundances: the relative abundance of Planctomycetes is 50.92% to 53.00%, the relative abundance of Chloroflexi is 19.32% to 20.11%, the relative abundance of Proteobacteria is 11.11% to 11.57%, the relative abundance of Bacteroidetes is 10.46% to 10.89%, the relative abundance of Firmicutes is 2.81% to 2.93%, and the relative abundance of Gemmatimonadetes is 1.85% to 1.93%; (4) inputting the to-be-treated nitrogen-containing wastewater into the integrated submerged biofilter, and stably operating, wherein the to-be-treated nitrogen-containing wastewater contains ammonia nitrogen and nitrite nitrogen, the concentration of the ammonia nitrogen in the to-be-treated nitrogen-containing wastewater is 78.0 to 318.3 mg / L, and the concentration of the nitrite nitrogen in the to-be-treated nitrogen-containing wastewater is 52.7 to 348.9 mg / L.

2. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and the ANAMMOX bacteria according to claim 1, characterized in that, When 15% to 20% of the area of the reactor inner wall of the integrated submerged biofilter is grown and attached with Chlorella, and the microbial community meets the following conditions, the system is successfully started; The microbial community in the activated sludge in the integrated submerged biofilter comprises the following microorganisms with the following relative abundances: the relative abundance of Planctomycetes is 51.96%, the relative abundance of Chloroflexi is 19.72%, the relative abundance of Proteobacteria is 11.34%, the relative abundance of Bacteroidetes is 10.68%, the relative abundance of Firmicutes is 2.87%, and the relative abundance of Gemmatimonadetes is 1.89%.

3. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and the ANAMMOX bacteria according to claim 1, characterized in that, In step (1), the MLSS concentration of the sludge is 6500 to 8500 mg / L, and the pH of the sludge is 6.0 to 9.

0.

4. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, In step (1), the inert gas is introduced to control the air pressure in the integrated submerged biofilter at 0.15 to 0.20 Mpa, the continuous aeration time is 30 to 60 h, and the aeration is followed by standing for 10 to 20 min.

5. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, In step (4), the DO in the reaction system is controlled at 0, the pH is controlled at 5.57 to 9.97, and the water temperature is controlled at 26.5 to 32.6℃.

6. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, The integrated submerged biofilter is provided with a combined filler, which is composed of a filler single piece, a plastic sleeve and a central copper tube wire, and the structure of the combined filler is that a plastic round piece is buckled into a double-ring large plastic ring, and polyester silk is pressed on the ring of the double-ring large plastic ring to make the fiber bundles uniformly distributed; the inner ring of the double-ring large plastic ring is a snowflake-shaped plastic branch.

7. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, The hydraulic retention time in step (2) is 14 to 18 hours, the hydraulic retention time in step (3) is 14 to 18 hours, and the hydraulic retention time in step (4) is 14 to 18 hours.

8. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, The step (2) does not discharge the bottom mud; the step (3) does not discharge the bottom mud, and the step (4) does not discharge the bottom mud.

9. The method for treating low C / N nitrogen-containing wastewater with high efficiency by using the algae and ANAMMOX bacteria according to claim 1, characterized in that, In the step (1), the ratio of the amount of the biofilm active sludge to the effective volume of the integrated submerged biological filter is (0.8~1.0):1.

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