Application of a low-energy denitrification complex microbial community in activated sludge systems

Abstract

This invention relates to the field of water pollution control technology, specifically disclosing the application of a low-energy denitrification composite microbial community in activated sludge systems. The *Alcaligenes* HO-1 provided by this invention can achieve one-step denitrification through direct ammonia oxidation under aerobic conditions, while *Pseudomonas* AD-1 can denitrify under aerobic conditions. This synergistic effect significantly shortens the treatment time of traditional denitrification processes and reduces the release of greenhouse gases (such as N2O) during traditional denitrification, contributing to greener and lower-carbon wastewater treatment. The technology provided by this invention effectively solves the problems of high energy consumption and multiple pathways in traditional denitrification processes. By applying a coupled process of direct ammonia oxidation and aerobic denitrification, the reaction steps in the process can be reduced, significantly reducing energy consumption during treatment, which meets the green development requirements of energy conservation, cost reduction, and efficiency improvement.

Description

Technical Field

[0001] This invention relates to the field of water pollution control technology, specifically to the application of a low-energy denitrification composite microbial community in an activated sludge system. Background Technology

[0002] Eutrophication has become a pressing global environmental problem, primarily caused by the excessive accumulation of nutrients such as nitrogen and phosphorus. Excessive nutrient discharge directly leads to ecological imbalance in aquatic environments, triggering a series of ecological crises such as algal blooms and oxygen depletion, severely threatening water quality and biodiversity. Furthermore, eutrophication exacerbates greenhouse gas emissions, especially the potent greenhouse gas nitrous oxide (N2O). Therefore, exploring efficient denitrification strategies is crucial for ensuring the sustainability of water resource reuse and environmental health.

[0003] Currently, the most commonly used nitrogen removal technologies in wastewater treatment plants are biological nitrogen removal processes based on activated sludge systems. SBR (Sequencing Batch Reactor), AAO (Anaerobic-Anoxic-Aerobic), and oxidation ditch processes are the mainstream technologies in my country's wastewater treatment plants, accounting for over 80%. Microbial-driven nitrogen transformation is a highly efficient and environmentally friendly treatment process based on various biological metabolic activities. The traditional nitrification-denitrification process is the most important nitrogen removal pathway, where nitrifying bacteria convert ammonia nitrogen into nitrate, and denitrifying bacteria reduce nitrate back to nitrogen gas. This process alternates between aerobic and anaerobic conditions, effectively removing nitrogen from wastewater. Furthermore, to meet the demands for more efficient and environmentally friendly treatment, novel biological nitrogen removal technologies such as aerobic denitrification, anaerobic ammonium oxidation, and direct ammonium oxidation have emerged. Anaerobic ammonium oxidation (ANAMMOX) converts ammonia nitrogen and nitrite into nitrogen gas under anaerobic conditions using anaerobic ammonium-oxidizing bacteria. It has low energy consumption and high nitrogen removal efficiency, and can be applied on a large scale in sludge digester denitrification. Nitrification and denitrification can occur simultaneously under aerobic conditions, minimizing the generation of secondary pollutants and negatively impacting the environment, making them particularly suitable for treating high-nitrogen wastewater. Direct ammonia oxidation (Dirammox) is an emerging and highly promising nitrogen removal method that directly converts ammonia (NH3) into nitrogen gas by oxidizing it to transient hydroxylamine. This emerging technology achieves highly efficient nitrogen removal with few byproducts, showing broad application prospects. In wastewater treatment, selecting appropriate nitrogen removal technologies not only improves system efficiency but also reduces negative environmental impacts, providing a new solution for sustainable wastewater treatment and environmental protection.

[0004] Biological nitrogen removal efficiency is influenced by multiple factors, the most critical of which include nutrient availability, microbial activity, and environmental conditions (such as temperature, pH, and dissolved oxygen concentration). However, existing nitrogen removal methods still have limitations, especially in traditional nitrification-denitrification processes, which often face problems such as high organic carbon demand and high system energy consumption. In recent years, emerging nitrogen removal technologies such as anaerobic ammonia oxidation (ANAO), aerobic denitrification, and direct ammonia oxidation (DAO) have been proposed to address these issues. While they have achieved good nitrogen removal effects to varying degrees, they also have their own limitations. For example, ANAO has strict requirements for operating conditions, necessitates significant modifications to existing wastewater treatment facilities, and has a long start-up time, resulting in high implementation costs and operational complexity in practical applications. Aerobic denitrification technology's nitrogen removal efficiency is highly dependent on the stability of the microbial community and is sensitive to environmental parameters. Although DAO shows high efficiency in ammonia nitrogen removal, its ability to remove nitrite and nitrate nitrogen is relatively weak, limiting its wider application. Incomplete nitrogen removal not only significantly increases operating costs but may also lead to the risk of secondary pollution. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an application of a low-energy denitrification composite microbial community in activated sludge systems. The present invention aims to construct a direct ammonia oxidation and aerobic denitrification composite denitrification microbial community and to construct an artificial multicellular system through bioaugmentation, thereby steadily improving the treatment efficiency of nitrogen pollutants in wastewater and significantly reducing the energy consumption of the system.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] Application of a low-energy denitrification complex in activated sludge systems, wherein the denitrification complex includes Alcaligenes HO-1 and Pseudomonas AD-1.

[0008] In the technical solution disclosed in this invention, the specific operation steps are as follows: after the activated sludge system has been running stably, Alcaligenes HO-1 bacterial solution and Pseudomonas AD-1 bacterial solution are directly added to the activated sludge system.

[0009] In the technical solution disclosed in this invention, the Alcaligenes HO-1 bacterial solution accounts for 0.5-2% of the wastewater volume. In some embodiments of this invention, for example, 0.5%, 1%, 1.5%, or 2% can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0010] In the technical solution disclosed in this invention, the Pseudomonas AD-1 bacterial solution accounts for 0.5-2% of the wastewater volume. In some embodiments of this invention, for example, 0.5%, 1%, 1.5%, or 2% can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] In the technical solution disclosed in this invention, the viable count of the Alcaligenes HO-1 bacterial solution is not less than 1.0 × 10⁻⁶. 8 cfu / mL.

[0012] In the technical solution disclosed in this invention, the viable count of the Pseudomonas AD-1 bacterial solution is not less than 1.0 × 10⁻⁶. 8 cfu / mL.

[0013] In the technical solution disclosed in this invention, the specific operation steps also include: after the activated sludge system has been running stably, first fill the carrier, and then add Alcaligenes HO-1 bacterial solution and Pseudomonas AD-1 bacterial solution to the activated sludge system.

[0014] In the technical solution disclosed in this invention, the carrier is selected from polyurethane foam.

[0015] In the technical solutions disclosed in this invention, the loading rate of the carrier is 30-50%. In some embodiments of this invention, for example, 30%, 35%, 40%, 45%, and 50% can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The Alcaligenes HO-1 provided by this invention has a high ammonia nitrogen (NH4) content. + It exhibits excellent degradation performance of chemical oxygen demand (COD) and total phosphorus (TP), and is highly adaptable to environmental conditions; Pseudomonas AD-1 also shows excellent degradation performance of chemical oxygen demand (COD) and nitrate nitrogen (NO3). - -N) and nitrite nitrogen (NO2) - -N) exhibits highly efficient degradation capabilities; this invention couples these two strains to construct a functionally complementary, comprehensive, and stable denitrifying bacterial community. This composite bacterial community not only significantly enhances the denitrification efficiency of the activated sludge system but also improves the system's operational stability, enabling it to better adapt to fluctuations in wastewater quality and reduce the impact of external condition changes on treatment effectiveness. Therefore, the composite bacterial community technology provided by this invention has extremely high application value and wide applicability in existing wastewater treatment facilities.

[0018] (2) The Alcaligenes HO-1 provided by this invention can achieve one-step denitrification through direct ammonia oxidation, while Pseudomonas AD-1 can achieve denitrification in an aerobic tank. This synergistic effect significantly shortens the treatment time of traditional denitrification processes and reduces the release of greenhouse gases (such as N2O) during traditional denitrification processes, which helps to achieve greener and lower carbon wastewater treatment. The technology provided by this invention effectively solves the problems of high energy consumption and multiple pathways in traditional denitrification processes. By applying the coupling process of direct ammonia oxidation and aerobic denitrification, the reaction steps in the process can be reduced, significantly reducing the energy consumption in the treatment process, which meets the green development requirements of energy saving, cost reduction and efficiency improvement.

[0019] (3) The Alcaligenes HO-1 and Pseudomonas AD-1 provided by this invention are both aerobic microorganisms that can be seamlessly integrated into existing processes without the need for large-scale modifications to existing facilities. This not only significantly improves the denitrification capacity of existing systems, enabling them to meet stricter emission standards, but also greatly reduces modification costs and operational risks. Therefore, this invention has broad application potential and high feasibility in the upgrading and renovation of wastewater treatment plants. Attached Figure Description

[0020] Figure 1 This is an electron microscope image of the polyurethane sponge loaded with bacterial flora in Example 1 of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0022] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0023] The Alcaligenes HO-1 used in this invention was purchased from the Institute of Microbiology, Chinese Academy of Sciences, with accession number CGMCC No. 16549.

[0024] The Pseudomonas AD-1 used in this invention has been disclosed in patent document CN115490340A and master's thesis "Construction of Aerobic Denitrifying Bacteria and Study on Enhanced A / O Process Denitrification Performance" by Jing Fangyuan, Huazhong University of Science and Technology. It can be purchased by the public from Huazhong University of Science and Technology.

[0025] Preparation of Alcaligenes HO-1 bacterial suspension: Alcaligenes HO-1 strain was streaked on plates, purified colonies were picked and expanded in LB medium to obtain Alcaligenes HO-1 bacterial suspension. The viable count of Alcaligenes HO-1 bacterial suspension used in this invention was 1.0 × 10⁻⁶. 8 cfu / mL;

[0026] Preparation of Pseudomonas AD-1 bacterial suspension: Pseudomonas AD-1 strain was streaked onto plates, purified colonies were picked, and then expanded into LB medium to obtain Pseudomonas AD-1 bacterial suspension. The viable count of the Pseudomonas AD-1 bacterial suspension used in this invention was 1.0 × 10⁻⁶. 8 cfu / mL;

[0027] The viable count of Alcaligenes faecalis CICC 22642 bacterial suspension was 1.0 × 10⁻⁶. 8 cfu / mL;

[0028] The LB medium consists of: 10g peptone, 5g yeast extract, 5g NaCl, and 1L distilled water.

[0029] Example 1

[0030] The application of a low-energy denitrification composite microbial community in an activated sludge system includes the following steps:

[0031] (1) The influent is actual wastewater from a municipal wastewater treatment plant, and the composition and content of pollutants are as follows: COD 280mg / L, TN 30.0mg / L, NO3 - -N 1.5mg / L, NH4 + -N 25mg / L, TP 2.5mg / L, wastewater treatment system is A 2 The / O device has an effective volume of 410L, with an anaerobic:anoxic:aerobic tank volume ratio of 1:1:3. The anaerobic tank dimensions are 460mm × 400mm × 500mm. Wastewater overflows from the top of the baffle to the anoxic tank. A pipe at the bottom of the anoxic tank connects to the bottom of the first aerobic tank, and then overflows from the end of the aerobic tank into a sedimentation tank. The sedimentation tank is a radial flow sedimentation tank with dimensions of [missing information]. The anaerobic and anoxic tanks utilize a mixer to thoroughly mix the sludge, while the aerobic tank is equipped with aeration pipes at the bottom, and the aeration rate is precisely controlled by a flow meter. A water storage tank is located at the front end of the reactor, from which domestic sewage is pumped daily to meet treatment needs.

[0032] (2) In summer, the experimental apparatus was started and operated continuously. The sludge inoculation concentration was approximately 3000 mg / L, and the mixed liquor and sludge return ratio were both set to 200%. After stable operation, 2cm*2cm polyurethane sponges were placed in the aerobic tank of AAO at a 50% filling rate. 1% (v / v) Alcaligenes HO-1 bacterial solution and 1% (v / v) Pseudomonas AD-1 bacterial solution were added to the activated sludge treatment system, and the system was adjusted. After the bacterial addition system stabilized, the mixed liquor return ratio was adjusted to 50%, and the system was continuously run to analyze the treatment efficiency of domestic sewage. The water sample was centrifuged at 8000 r / min for 5 min and filtered through a 0.22 μm filter membrane. The total nitrogen (TN) and ammonia nitrogen (NH4) in the influent and effluent were measured daily. + -N), nitrate nitrogen (NO3) - -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0033] Experimental results analysis: The AAO device operated for a total of 60 days, with the mixed liquor and sludge return ratio both set at 200%. In a pure activated sludge system, the TN and NH4+ levels during the stable phase were... + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of nitrogen (TN) were 14.72 mg / L, 9.75 mg / L, and 4.06 mg / L, respectively, and the concentrations of total nitrogen (TN) and NH4+ were also found to be... + -N removal rates were 50.9% and 61.00%, respectively, with COD and TP concentrations in the effluent being 18.37 mg / L and 0.43 mg / L, respectively. After adding a mixed bacterial community of Alcaligenes HO-1 and Pseudomonas AD-1, TN and NH4+ levels remained stable during the steady-state phase. + -N and NO x — The nitrogen concentrations in the effluent were 6.02 mg / L, 4.98 mg / L, and 2.51 mg / L, respectively, and the TN and NH4 concentrations were also high. + The removal rates of -N were 79.93% and 80.08%, respectively, and the effluent concentrations of COD and TP were 8.21 mg / L and 0.16 mg / L, respectively. The daily power consumption of the mixed liquor reflux pump was 1.06 kWh.

[0034] After reducing the reflux ratio of the mixture from 200% to 50%, the TN and NH4+ content in the stable phase... + -N and NO x —The effluent concentrations of nitrogen (N) were 5.98 mg / L, 5.25 mg / L, and 1.55 mg / L, respectively; the effluent concentrations of COD and TP were 5.51 mg / L and 0.12 mg / L, respectively; and the daily power consumption of the mixed liquor reflux pump was 0.76 kWh. Therefore, the TN removal efficiency achieved a significant improvement of 19.68%, mainly due to NH4+. + -N removal efficiency improved by 16%, intermediate NO x — Nitrogen (N) was reduced by 38.1%, while the effluent concentrations of COD and TP were also significantly reduced. Even with a mixed liquor reflux ratio reduced to 50%, the composite microbial system maintained a high removal rate for pollutants, while simultaneously achieving a 30% reduction in system energy consumption. This demonstrates that the composite microbial system provided by this invention can facilitate more comprehensive and efficient removal of various forms of nitrogen pollutants.

[0035] Polyurethane sponges loaded with bacterial colonies were collected, and the bacterial load was observed using field emission scanning electron microscopy (SEM). The results are as follows: Figure 1 As shown, from Figure 1 As can be seen, the bacterial community is evenly distributed on the polyurethane sponge, and grows and attaches in the pores of the sponge, forming a stable biofilm structure. There is no obvious shedding or aggregation on the surface, indicating that the bacteria can effectively colonize the sponge surface and maintain their activity. These observations prove that the polyurethane sponge, as a carrier, can provide sufficient surface area and microenvironment to support the good loading and growth of Pseudomonas AD-1 and Alcaligenes HO-1 bacterial communities.

[0036] Example 2

[0037] The application of a low-energy denitrification composite microbial community in an activated sludge system includes the following steps:

[0038] (1) Prepare simulated domestic sewage according to the influent indicators of the sewage treatment plant. The pollutant composition and content are: COD 350mg / L, TN 40mg / L, NO3 - -N 5mg / L, NH4 + -N 35mg / L, TP 3.2mg / L; the experimental setup was an SBR reactor (effective volume 1.2L), the operating cycle was set to 24h, including 15min for influent and effluent, 16h for aeration (DO 3mg / L), and 7.5h for settling, the concentration of activated sludge in the system was approximately 300mg / L.

[0039] (2) The experimental setup was started and run continuously. After the operation stabilized, 1% (v / v) Alcaligenes HO-1 bacterial solution and 1% (v / v) Pseudomonas AD-1 bacterial solution were added to the activated sludge treatment system. The HRT was adjusted to 12h, with 15min for both influent and effluent, 8h for aeration (DO of 3mg / L), and 3.5h for settling. The treatment efficiency of the system for pollutants was analyzed. The water sample was centrifuged at 8000r / min for 5min and filtered through a 0.22μm filter membrane. The total nitrogen (TN) and ammonia nitrogen (NH4) in the influent and effluent were measured daily. + -N), nitrate nitrogen (NO3) - -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0040] Experimental results analysis: The SBR unit operated for a total of 30 days, and the pure activated sludge system reached a stable stage, with TN and NH4 levels decreasing. + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of TN, NH4+, and PM2.5 were 18.54 mg / L, 0.87 mg / L, and 16.86 mg / L, respectively. After adding the mixed bacterial culture, the concentrations of TN and NH4+ decreased. + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of TN, NH4+, and NH4+ were 6.80 mg / L, 0.35 mg / L, and 3.16 mg / L, respectively. After the HRT was reduced to 12 h, the concentrations of TN and NH4+ in the effluent were... + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of nitrogen (TN) were 6.35 mg / L, 0.13 mg / L, and 3.58 mg / L, respectively. The results showed that the addition of mixed microbial communities significantly improved the removal rate of TN, reducing the effluent concentration from 18.54 mg / L to 6.80 mg / L, achieving a removal rate of 63.3%. Meanwhile, NO... x —The nitrogen concentration also decreased significantly by 13.7 mg / L, indicating a reduction in the accumulation of intermediate products and a significant improvement in the system's denitrification effect. Even after the HRT was reduced to 12 h, the composite microbial community system maintained a high removal rate for pollutants. This demonstrates that the mixed microbial community of Alcaligenes HO-1 and Pseudomonas AD-1 effectively improves TN removal efficiency and inhibits the generation of intermediate products. Furthermore, the optimization of the HRT significantly enhances the system's pollutant treatment efficiency and accelerates the wastewater treatment process, further proving the high efficiency of the coupling between Alcaligenes HO-1 and Pseudomonas AD-1.

[0041] Example 3

[0042] The application of a low-energy denitrification composite microbial community in an activated sludge system includes the following steps:

[0043] (1) Prepare simulated domestic sewage according to the influent indicators of the sewage treatment plant. The pollutant composition and content are: COD 350mg / L, TN 40mg / L, NO3 - -N 5mg / L, NH4 + -N 35mg / L, TP 3.2mg / L; the experimental setup was an SBR reactor, with a reaction cycle set at 24h: 5min influent, 12h aeration, 11h25min settling, and 30min effluent. After each cycle, half the liquid was discharged, and simulated wastewater was added to replenish the volume to 1.2L. Aeration was performed using a BOD5-specific water sample pretreatment aerator, with air introduced into the reactor through an 8cm diameter aeration disc. During the aeration phase, DO was maintained at 4mg / L, and during the settling phase, it was 1mg / L. The final concentration of activated sludge in the system was 3000mg / L.

[0044] (2) The device was started and operated continuously. After the system stabilized, 1% (v / v) Alcaligenes HO-1 bacterial solution and 1% (v / v) Pseudomonas AD-1 bacterial solution were added to the activated sludge treatment system. To improve the abundance of denitrifying bacteria, a stronger bacterial solution was added every 7 days according to the above ratio. After the system containing the compound bacteria stabilized, the HRT was adjusted to 12h. The mixed liquid of the system after the influent was taken as the influent daily, and the supernatant of the system at the end of the settling period was taken as the effluent. The water sample was centrifuged at 8000r / min for 5min and filtered through a 0.22μm filter membrane. The total nitrogen (TN) and ammonia nitrogen (NH4) of the influent and effluent were measured daily. + -N), nitrate nitrogen (NO3) - -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0045] Experimental results analysis: The SBR unit operated for a total of 45 days, and the pure activated sludge system reached a stable stage, with TN and NH4 levels decreasing. + -N and NOx — N(NO3 — N and NO2 — The effluent concentrations of nitrogen (TN) were 16.99 mg / L, 0.75 mg / L, and 12.28 mg / L, respectively. After adding the mixed bacterial culture, the concentrations of TN and NH4+ in the effluent decreased. + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of TN, NH4+, and NH4+ were 7.57 mg / L, 0.19 mg / L, and 4.69 mg / L, respectively. After the HRT was reduced to 12 h, the concentrations of TN and NH4+ in the effluent were... + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of nitrogen (TN) were 6.57 mg / L, 0.15 mg / L, and 3.98 mg / L, respectively. Comparative analysis showed that the introduction of mixed microbial communities significantly improved TN removal efficiency, increasing removal efficiency by 21.05%. x — The significant reduction in N demonstrates that the nitrogen conversion process has been optimized. Even after the HRT was reduced to 12h, the composite microbial community system still maintained a high removal rate of pollutants, proving the high efficiency of the coupling of Alcaligenes HO-1 and Pseudomonas AD-1 mixed microbial community. The reduction in HRT helps the reactor process more wastewater per unit time, thereby improving the system's treatment capacity.

[0046] Comparative Example 1

[0047] The application of a denitrifying bacterial community in an activated sludge system includes the following steps:

[0048] (1) The influent is actual wastewater from a municipal wastewater treatment plant, and the composition and content of pollutants are as follows: COD 280mg / L, TN 30.0mg / L, NO3 - -N 1.5mg / L, NH4 + -N 25mg / L, TP 2.5mg / L. The wastewater treatment system is an A2 / O unit with an effective volume of 410L. The volume ratio of anaerobic tank: anoxic tank: aerobic tank is 1:1:3, with the anaerobic tank measuring 460mm×400mm×500mm. Wastewater overflows from the top of the baffle to the anoxic tank. A pipe at the bottom of the anoxic tank connects to the bottom of the first aerobic tank, and then overflows from the end of the aerobic tank into the sedimentation tank. The sedimentation tank is a radial flow sedimentation tank with dimensions of [missing information]. The anaerobic and anoxic tanks utilize a mixer to thoroughly mix the sludge, while the aerobic tank is equipped with aeration pipes at the bottom, and the aeration rate is precisely controlled by a flow meter. A water storage tank is located at the front end of the reactor, from which domestic sewage is pumped daily to meet treatment needs.

[0049] (2) Start the experimental setup and run it continuously. After the setup has stabilized, place 2cm*2cm polyurethane sponges at a 50% filling rate in the aerobic tank of the AAO system. Add 2% (v / v) Alcaligenes HO-1 bacterial solution to the stable activated sludge treatment system. Centrifuge the water sample at 8000r / min for 5min, filter it through a 0.22μm filter membrane, and measure the total nitrogen (TN) and ammonia nitrogen (NH4) in the influent and effluent daily. + -N), nitrate nitrogen (NO3) - -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0050] Experimental results analysis: The AAO device operated for a total of 80 days, with the mixed liquor and sludge return ratio both set at 200%. In a pure activated sludge system, the TN and NH4+ levels during the stable phase were... + -N and NO x — The nitrogen concentrations in the effluent were 20.38 mg / L, 15.70 mg / L, and 1.95 mg / L, respectively, and the TN and NH4 concentrations were also high. + -N removal rates were 32.06% and 37.20%, respectively; after adding Alcaligenes HO-1, TN and NH4+ in the stable phase were... + -N and NO x — The nitrogen concentrations in the effluent were 14.63 mg / L, 7.82 mg / L, and 1.74 mg / L, respectively, and the TN and NH4 concentrations were also high. + The removal rates of nitrogen (TN) and nitrogen (NH4+) were 51.23% and 68.72%, respectively. Before and after system construction, the average effluent TP concentration decreased from 0.97 mg / L to approximately 0.31 mg / L, representing an increase in the average removal rate of 26.40%. The average effluent COD concentration decreased by 24.8 mg / L. These results indicate that *Alcaligenes* HO-1, possessing direct ammonia oxidation function, can significantly improve TN and NH4+ removal. + The removal efficiency of -N was improved by 19.16% and the removal rate by 31.52%, respectively, showing good potential in improving TN removal. However, it did not significantly improve the removal efficiency of NO already present in the water. x — The removal effect of N is relatively poor, NO x —The nitrogen concentration decreased only slightly from 1.93 mg / L to 1.74 mg / L. This indicates that although the Alcaligenes species played a positive role in the overall nitrogen removal, further optimization is needed in the conversion and removal of nitrite and nitrate.

[0051] Comparative Example 2

[0052] The application of a denitrifying bacterial community in an activated sludge system includes the following steps:

[0053] (1) The influent is actual wastewater from a municipal wastewater treatment plant, and the composition and content of pollutants are as follows: COD 280mg / L, TN 30.0mg / L, NO3 - -N 1.5mg / L, NH4 + -N 25mg / L, TP 2.5mg / L. The wastewater treatment system is an A2 / O unit with an effective volume of 410L. The volume ratio of anaerobic tank: anoxic tank: aerobic tank is 1:1:3, with the anaerobic tank measuring 460mm×400mm×500mm. Wastewater overflows from the top of the baffle to the anoxic tank. A pipe at the bottom of the anoxic tank connects to the bottom of the first aerobic tank, and then overflows from the end of the aerobic tank into the sedimentation tank. The sedimentation tank is a radial flow sedimentation tank with dimensions of [missing information]. The anaerobic and anoxic tanks utilize a mixer to thoroughly mix the sludge, while the aerobic tank is equipped with aeration pipes at the bottom, and the aeration rate is precisely controlled by a flow meter. A water storage tank is located at the front end of the reactor, from which domestic sewage is pumped daily to meet treatment needs.

[0054] (2) Start the experimental setup and run it continuously. After the setup has stabilized, place 2cm*2cm polyurethane sponges at a 50% filling rate in the aerobic tank of the AAO system. Add 2% (v / v) of Pseudomonas AD-1 bacterial solution to the stable activated sludge treatment system. Centrifuge the water sample at 8000r / min for 5min, filter it through a 0.22μm filter membrane, and measure the total nitrogen (TN) and ammonia nitrogen (NH4) in the influent and effluent daily. + -N), nitrate nitrogen (NO3) - -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0055] Experimental results analysis: The reactor operated for a total of 60 days. During the stable operation of the pure activated sludge reactor, the TN and NH4+ levels were as follows: + -N and NO x —The nitrogen (N) concentrations in the effluent were 13.34 mg / L, 6.58 mg / L, and 5.18 mg / L, respectively, with a total nitrogen (TN) removal rate of 55.53%. After adding *Pseudomonas aeruginosa* AD-1 bacterial culture with HN-AD function, the TN and NH4+ levels remained stable during the steady-state phase. + -N and NO x — The nitrogen (N) concentrations in the effluent were 9.62 mg / L, 5.96 mg / L, and 0.24 mg / L, respectively, with a total nitrogen (TN) removal rate of 67.9%. This indicates that the enhancement effect of Pseudomonas AD-1 on TN removal in the activated sludge system is relatively limited, with a TN removal efficiency improvement of 12.4%, mainly attributed to NO... x — Improved nitrogen removal efficiency, and improved removal efficiency for NH4 + The improvement in -N removal efficiency was limited, with an increase of only 0.62 mg / L.

[0056] Comparative Example 3

[0057] The application of a denitrifying complex microbial community in an activated sludge system includes the following steps:

[0058] (1) The influent is actual wastewater from a municipal wastewater treatment plant, and the composition and content of pollutants are as follows: COD 280mg / L, TN 30.0mg / L, NO3 - -N 1.5mg / L, NH4 + -N 25mg / L, TP 2.5mg / L. The wastewater treatment system is an A2 / O unit with an effective volume of 410L. The volume ratio of anaerobic tank: anoxic tank: aerobic tank is 1:1:3, with the anaerobic tank measuring 460mm×400mm×500mm. Wastewater overflows from the top of the baffle to the anoxic tank. A pipe at the bottom of the anoxic tank connects to the bottom of the first aerobic tank, and then overflows from the end of the aerobic tank into the sedimentation tank. The sedimentation tank is a radial flow sedimentation tank with dimensions of [missing information]. The anaerobic and anoxic tanks utilize a mixer to thoroughly mix the sludge, while the aerobic tank is equipped with aeration pipes at the bottom, and the aeration rate is precisely controlled by a flow meter. A water storage tank is located at the front end of the reactor, from which domestic sewage is pumped daily to meet treatment needs.

[0059] (2) Start the experimental setup and run it continuously. After the setup stabilizes, place 2cm*2cm polyurethane sponges at a 50% filling rate in the aerobic tank of the AAO. Add 1% (v / v) Alcaligenes HO-1 bacterial solution and 1% (v / v) Alcaligenes faecalis CICC 22642 bacterial solution to the activated sludge treatment system. Centrifuge the water sample at 8000r / min for 5min, filter it through a 0.22μm filter membrane, and measure the total nitrogen (TN) and ammonia nitrogen (NH4) in the influent and effluent daily. + -N), nitrate nitrogen (NO3)- -N), nitrite nitrogen (NO2) - The concentrations of N, total phosphorus (TP), and chemical oxygen demand (COD).

[0060] Experimental results analysis: The AAO device operated for a total of 60 days, with the mixed liquor and sludge return ratio both set at 200%. In a pure activated sludge system, the TN and NH4+ levels during the stable phase were... + -N and NO x — N(NO3 — N and NO2 — The effluent concentrations of nitrogen (TN) were 13.25 mg / L, 10.36 mg / L, and 4.23 mg / L, respectively. + -N removal rates were 55.83% and 58.56%, respectively, with COD and TP effluent concentrations of 14.27 mg / L and 0.68 mg / L, respectively. After adding a mixed bacterial culture of *Alcaligenes HO-1* and *Alcaligenes faecalis* CICC 22642, TN and NH4+ levels remained stable during the stabilization phase. + -N and NO x — The nitrogen concentrations in the effluent were 8.55 mg / L, 5.09 mg / L, and 3.51 mg / L, respectively, and the TN and NH4 concentrations were also high. + The removal rates of -N were 71.50% and 79.64%, respectively, and the effluent concentrations of COD and TP were 12.21 mg / L and 0.36 mg / L, respectively. The daily power consumption of the mixed liquor reflux pump was 1.06 kWh.

[0061] After reducing the reflux ratio of the mixture from 200% to 50%, the TN and NH4+ content in the stable phase... + -N and NO x — The nitrogen concentrations in the effluent were 11.32 mg / L, 7.28 mg / L, and 5.67 mg / L, respectively, and the TN and NH4 concentrations were also high. + The removal rates of NH4+ and TP were 62.26% and 70.08%, respectively, with COD and TP concentrations in the effluent being 14.13 mg / L and 0.55 mg / L, respectively. The daily power consumption of the mixed liquor reflux pump was 0.76 kWh. Therefore, at a reflux ratio of 200%, the TN removal efficiency was improved by 15.67%, mainly due to NH4+. + -N removal efficiency was optimized by 21.08%. However, when the mixed liquor reflux ratio was reduced to 50%, the water quality deteriorated, indicating that the system of Alcaligenes HO-1 and Alcaligenes faecalis CICC22642 was not suitable for the process conditions.

[0062] The mixed bacterial system in Example 1 of this invention can still operate effectively when the mixed liquid reflux ratio is reduced to 50%, and the daily power consumption of the mixed liquid reflux pump is 0.76 kWh. In contrast, the mixed bacterial system in Comparative Example 3 cannot operate effectively when the mixed liquid reflux ratio is reduced to 50%, and can only operate effectively when the mixed liquid reflux ratio is 200%, and the daily power consumption of the mixed liquid reflux pump is 1.06 kWh. Compared with Comparative Example 3, Example 1 of this invention can operate at a low mixed liquid reflux ratio, achieving a 30% reduction in system energy consumption, significantly reducing energy consumption in the treatment process, and meeting the green development requirements of energy conservation, cost reduction and efficiency improvement.

[0063] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. The application of a low-energy-consumption denitrification composite microbial community in an activated sludge system, characterized in that, The denitrifying complex microbial community includes Alcaligenes HO-1 and Pseudomonas AD-1; Among them, the alkali-producing bacillus HO-1 is an alkali-producing bacillus ( Alcaligenes sp.) HO-1 was deposited at the China General Microbiological Culture Collection Center on September 28, 2018, with accession number CGMCC No.16549; The Pseudomonas AD-1 is a type of Pseudomonas ( Pseudomonas sp.) AD-1.

2. The application according to claim 1, characterized in that, The specific operating steps are as follows: After the activated sludge system has been running stably, add Alcaligenes HO-1 bacterial solution and Pseudomonas AD-1 bacterial solution directly into the activated sludge system.

3. The application according to claim 2, characterized in that, The Alcaligenes HO-1 bacterial solution accounts for 0.5-2% of the wastewater volume.

4. The application according to claim 2, characterized in that, The Pseudomonas AD-1 bacterial solution accounted for 0.5-2% of the wastewater volume.

5. The application according to claim 2, characterized in that, The viable count of the Alcaligenes HO-1 bacterial suspension is not less than 1.0 × 10⁻⁶. 8 cfu / mL.

6. The application according to claim 2, characterized in that, The viable count of the Pseudomonas AD-1 bacterial suspension is not less than 1.0 × 10⁻⁶. 8 cfu / mL.

7. The application according to claim 1, characterized in that, The specific operating steps also include: after the activated sludge system has been running stably, first fill the carrier, and then add Alcaligenes HO-1 bacterial solution and Pseudomonas AD-1 bacterial solution to the activated sludge system.

8. The application according to claim 7, characterized in that, The carrier is selected from polyurethane foam.

9. The application according to claim 7, characterized in that, The carrier has a filling rate of 30-50%.

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