Application of low-energy-consumption denitrification composite flora in activated sludge system

Abstract

The invention relates to the technical field of water pollution control, and particularly discloses application of a low-energy-consumption denitrification composite flora in an activated sludge system.The alcaligenes HO-1 can achieve one-step denitrification through the direct ammoxidation effect under the aerobic condition, and the pseudomonas AD-1 can achieve denitrification nitrogen removal under the aerobic condition; due to the synergistic effect, the treatment time of a traditional denitrification process is remarkably shortened, meanwhile, release of greenhouse gas (such as N2O) in the traditional denitrification process is reduced, and greener and low-carbon sewage treatment can be achieved; according to the technology provided by the invention, the problems of high energy consumption and multiple ways of a traditional denitrification process are effectively solved, reaction steps in the process flow can be reduced by applying a direct ammoxidation and aerobic denitrification coupling process, the energy consumption in the treatment process is remarkably reduced, and the green development requirements of energy conservation, consumption reduction, cost reduction and efficiency improvement are met.

Description

Technical Field

[0001] The present invention relates to the technical field of water pollution control, and particularly to the application of a low-energy consumption denitrifying composite flora in an activated sludge system. Background Art

[0002] Water eutrophication has become an environmental problem that urgently needs to be solved globally, mainly caused by the excessive accumulation of nutrients such as nitrogen and phosphorus. The excessive discharge of nutrients directly leads to the ecological imbalance of the aquatic environment, and then triggers a series of ecological crises such as algal blooms and oxygen depletion, seriously threatening water quality and biodiversity. In addition, water eutrophication also exacerbates greenhouse gas emissions, especially the potent greenhouse gas nitrous oxide (N 2 O). Therefore, exploring efficient denitrification strategies is crucial for ensuring the sustainability of water resource reuse and environmental health.

[0003] Currently, the commonly used denitrification technologies in wastewater treatment plants are mainly biological denitrification processes based on activated sludge systems. Processes such as SBR (Sequencing Batch Reactor), AAO (Anaerobic-Anoxic-Oxic), and oxidation ditches are the mainstream processes in Chinese wastewater treatment plants, accounting for more than 80%. Microbe-driven nitrogen conversion is an efficient and environmentally friendly treatment process based on various biological metabolic activities. The traditional nitrification-denitrification process is the most important denitrification pathway, that is, ammonia nitrogen is converted into nitrate by nitrifying bacteria, and then nitrate is reduced to nitrogen gas by denitrifying bacteria. This process alternates between aerobic and anaerobic conditions and can effectively remove nitrogen from sewage. In addition, to meet the requirements of more efficient and environmentally friendly treatment, new biological denitrification technologies such as aerobic denitrification, anaerobic ammonium oxidation, and direct ammonia oxidation have emerged. Anaerobic ammonium oxidation (ANAMMOX) is the conversion of ammonia nitrogen and nitrite into nitrogen gas by anaerobic ammonium oxidizing bacteria under anaerobic conditions, with low energy consumption and high nitrogen removal efficiency, and can be applied on a large scale in the denitrification of sludge digestion liquid. Nitrification and denitrification can be carried out simultaneously under aerobic conditions, are not easy to produce secondary pollutants, and have less negative impact on the environment, especially suitable for the treatment of high-nitrogen wastewater. The direct ammonia oxidation method (Dirammox) is an emerging and promising denitrification method, which directly converts ammonia (NH 3 ) into nitrogen gas after oxidizing it to transient hydroxylamine. This emerging technology can achieve efficient denitrification with few by-products and has broad application prospects. In the process of wastewater treatment, selecting the appropriate denitrification technology not only improves the denitrification efficiency of the system, but also reduces the negative impact on the environment, providing a new solution for sustainable wastewater treatment and environmental protection.

[0004] The efficiency of biological nitrogen removal is affected by multiple factors, among which the most crucial ones include the availability of nutrients, the activity of microorganisms, and environmental conditions (such as temperature, pH, dissolved oxygen concentration, etc.). However, existing nitrogen removal methods still have certain limitations. Especially in the traditional nitrification-denitrification process, problems such as high demand for organic carbon and high system energy consumption are often faced. In recent years, emerging nitrogen removal technologies such as anaerobic ammonium oxidation, aerobic denitrification, and direct ammonia oxidation proposed for these problems have achieved good nitrogen removal effects to varying degrees, but each also has some limitations. For example, anaerobic ammonium oxidation has relatively strict requirements for operating conditions, requires significant modification of existing sewage treatment facilities, has a long start-up time, and has high implementation costs and operation complexity in practical applications. The nitrogen removal effect of aerobic denitrification technology highly depends on the stability of the microbial community and is relatively sensitive to environmental parameters. Although direct ammonia oxidation technology shows high efficiency in ammonia nitrogen removal, its ability to remove nitrite nitrogen and nitrate nitrogen is relatively weak, and this limitation restricts its promotion in more extensive application scenarios. The incomplete nitrogen removal effect not only greatly increases the operating cost but also may bring the risk of secondary pollution. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide an application of a low-energy-consumption nitrogen-removing composite bacterial community in an activated sludge system. The present invention aims to construct a composite nitrogen-removing bacterial community of direct ammonia oxidation and aerobic denitrification, and construct an artificial multi-cellular system through biological enhancement means, so as to stably improve the treatment efficiency of nitrogen pollutants in sewage and significantly reduce the energy consumption of the system.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] An application of a low-energy-consumption nitrogen-removing composite bacterial community in an activated sludge system, wherein the nitrogen-removing composite bacterial community includes Alcaligenes sp. HO-1 and Pseudomonas sp. AD-1.

[0008] In the technical solution disclosed by the present invention, the specific operation steps are as follows: after the activated sludge system operates stably, directly add the Alcaligenes sp. HO-1 bacterial solution and the Pseudomonas sp. AD-1 bacterial solution to the activated sludge system.

[0009] In the technical solution disclosed by the present invention, the Alcaligenes sp. HO-1 bacterial solution accounts for 0.5-2% of the volume of sewage. In some embodiments of the present invention, for example, 0.5%, 1%, 1.5%, 2% can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0010] In the technical solution disclosed by the present invention, the Pseudomonas aeruginosa AD-1 bacterial liquid accounts for 0.5-2% of the volume of the sewage. In some embodiments of the present invention, for example, 0.5%, 1%, 1.5%, 2% can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

[0011] In the technical solution disclosed by the present invention, the viable count of the Alcaligenes faecalis HO-1 bacterial liquid is not less than 1.0×10 8 cfu / mL.

[0012] In the technical solution disclosed by the present invention, the viable count of the Pseudomonas aeruginosa AD-1 bacterial liquid is not less than 1.0×10 8 cfu / mL.

[0013] In the technical solution disclosed by the present invention, the specific operation steps further include: after the activated sludge system operates stably, first fill the carrier, and then add the Alcaligenes faecalis HO-1 bacterial liquid and the Pseudomonas aeruginosa AD-1 bacterial liquid to the activated sludge system.

[0014] In the technical solution disclosed by the present invention, the carrier is selected from polyurethane sponges.

[0015] In the technical solution disclosed by the present invention, the filling rate of the carrier is 30-50%. In some embodiments of the present invention, for example, 30%, 35%, 40%, 45%, 50% can be selected, but it is not limited to the listed values, and other unlisted values within the numerical range are equally applicable.

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

[0017] (1) The Alcaligenes faecalis HO-1 provided by the present invention has excellent degradation performance for ammonia nitrogen (NH 4 + -N) and total phosphorus (TP), and has strong adaptability to environmental conditions; Pseudomonas aeruginosa AD-1 shows high degradation ability for chemical oxygen demand (COD), nitrate nitrogen (NO 3 - -N) and nitrite nitrogen (NO 2 - -N); the present invention couples these two strains to construct a nitrogen-removing bacterial community with complementary functions, comprehensiveness and stability. This composite bacterial community not only significantly enhances the nitrogen-removing efficiency of the activated sludge system, but also enhances the operation stability of the system, enabling it to better adapt to the fluctuations of sewage quality and reducing the impact of external condition changes on the treatment effect. Therefore, the composite bacterial community technology provided by the present invention has extremely high application value and wide applicability in existing sewage treatment facilities.

[0018] (2) The Alcaligenes HO-1 provided by the present invention can achieve one-step denitrification through direct ammonia oxidation, while Pseudomonas AD-1 can achieve denitrification in the aerobic tank. This synergistic effect significantly shortens the treatment time of traditional denitrification processes and reduces the release of greenhouse gases (such as N 2 O) during traditional denitrification, contributing to more green and low-carbon sewage treatment; the technology provided by the present invention effectively solves the problems of high energy consumption and multiple pathways in traditional denitrification processes. By applying the coupled process of direct ammonia oxidation and aerobic denitrification, the reaction steps in the process flow can be reduced, significantly reducing the energy consumption during the treatment process, meeting the green development requirements of energy conservation, consumption reduction, cost reduction, and efficiency improvement.

[0019] (3) Both Alcaligenes HO-1 and Pseudomonas AD-1 provided by the present invention are aerobic microorganisms and can be seamlessly integrated into existing processes without large-scale modification of existing facilities; this not only significantly improves the denitrification ability of the existing system to meet more stringent discharge standards but also greatly reduces the transformation cost and operation risk; therefore, the present invention has broad application potential and high feasibility in the upgrading and transformation of sewage treatment plants. Brief Description of the Drawings

[0020] Figure 1 It is an electron micrograph of the polyurethane sponge loaded with the bacterial community in Example 1 of the present invention. Detailed Embodiments

[0021] The following further details the present invention through specific and preferred embodiments, but the present invention is not limited to the following embodiments.

[0022] It should be noted that unless otherwise specified, the chemical reagents involved in the present invention are purchased through commercial channels.

[0023] The Alcaligenes HO-1 used in the present invention was purchased from the Institute of Microbiology, Chinese Academy of Sciences, and the preservation number is CGMCC No. 16549.

[0024] The Pseudomonas AD-1 used in the present invention has been disclosed in the patent document CN115490340A and the master's degree thesis "Construction of Aerobic Denitrifying Bacterial Communities and Their Enhanced Denitrification Performance in A / O Process", Jing Fangyuan, Huazhong University of Science and Technology. The public can obtain it from Huazhong University of Science and Technology.

[0025] Preparation of Alcaligenes HO-1 bacterial solution: The Alcaligenes HO-1 strain was cultured by streaking on a plate, and the purified colonies were picked and cultured in an enlarged scale in LB medium to obtain the Alcaligenes HO-1 bacterial solution. The viable count of the Alcaligenes HO-1 bacterial solution used in the present invention is 1.0×10 8 cfu / mL;

[0026] Preparation of Pseudomonas aeruginosa AD-1 bacterial liquid: The Pseudomonas aeruginosa AD-1 strain was cultured by streaking on a plate. The purified colonies were picked and cultured in an enlarged scale in LB medium to obtain Pseudomonas aeruginosa AD-1 bacterial liquid. The viable count of the Pseudomonas aeruginosa AD-1 bacterial liquid used in the present invention is 1.0×10 8 cfu / mL;

[0027] The viable count of Alcaligenes faecalis CICC 22642 bacterial liquid is 1.0×10 8 cfu / mL;

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

[0029] Example 1

[0030] Application of a low-energy-consuming denitrifying complex bacterial community in an activated sludge system, comprising the following steps:

[0031] (1) The influent is the actual wastewater from a municipal sewage treatment plant, and the components and contents of pollutants are as follows: COD 280 mg / L, TN 30.0 mg / L, NO 3 - -N 1.5 mg / L, NH 4 + -N 25 mg / L, TP 2.5 mg / L. The sewage treatment system is an A 2 / O device. The effective volume of this system is 410 L, and the volume ratio of the anaerobic tank: anoxic tank: aerobic tank is 1:1:3. The anaerobic tank has a specification of 460 mm×400 mm×500 mm. The sewage overflows to the anoxic tank from the top of the partition board. There is a pipeline at the bottom of the side of the anoxic tank connected to the bottom of the first aerobic tank, and then enters the sedimentation tank through the overflow port at the end of the aerobic tank. The sedimentation tank is set as a radial flow sedimentation tank, with dimensions of The anaerobic tank and anoxic tank use stirrers to fully mix the sludge. An air diffuser is provided at the bottom of the aerobic tank, and the air flow rate is accurately controlled by a flow meter. A water storage bucket is arranged at the front end of the reactor, and domestic sewage is pumped from the water storage device every day by a submersible pump to meet the treatment requirements.

[0032] (2) In summer, start the experimental device and run it continuously. The sludge inoculation concentration is about 3000 mg / L, and the mixed liquor and sludge reflux ratios are both set at 200%. After stable operation, place 2 cm * 2 cm polyurethane sponges in the aerobic tank of AAO at a packing rate of 50%. Add 1% (v / v) Alcaligenes faecalis HO-1 bacterial solution and 1% (v / v) Pseudomonas aeruginosa AD-1 bacterial solution to the activated sludge treatment system and debug the system. After the system with added bacteria is stable, adjust the mixed liquor reflux ratio to 50% and continuously operate to analyze the treatment efficiency of the system for domestic sewage. Centrifuge the water sample at 8000 r / min for 5 min, filter it through a 0.22 μm filter membrane, and measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP), and chemical oxygen demand (COD) in the influent and effluent water daily.

[0033] Analysis of test results: The AAO device operated for a total of 60 days. The mixed liquor and sludge reflux ratios were both set at 200%, and it was a pure activated sludge system. During the stable stage, the effluent concentrations of TN, NH 4 + -N, and NO x — N (NO 3 — N and NO 2 — N) were 14.72 mg / L, 9.75 mg / L, and 4.06 mg / L respectively. The removal rates of TN and NH 4 + -N were 50.9% and 61.00% respectively, and the effluent concentrations of COD and TP were 18.37 mg / L and 0.43 mg / L respectively. After adding the mixed bacteria of Alcaligenes faecalis HO-1 and Pseudomonas aeruginosa AD-1, during the stable stage, the effluent concentrations of TN, NH 4 + -N, and NO x — N were 6.02 mg / L, 4.98 mg / L, and 2.51 mg / L respectively. The removal rates of TN and NH 4 + -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 mixed liquor reflux ratio from 200% to 50%, during the stable stage, TN, NH 4 + -N, and NOx — The effluent concentrations of TN are 5.98 mg / L, 5.25 mg / L and 1.55 mg / L respectively, and the effluent concentrations of COD and TP are 5.51 mg / L and 0.12 mg / L respectively. The daily power consumption of the mixed liquor return pump is 0.76 kWh. It can be seen that the TN removal efficiency has been significantly improved by 19.68%, mainly due to the 16% optimization of the NH 4 + -N removal efficiency, and the intermediate substance NO x — N has been reduced by 38.1%. At the same time, the effluent concentrations of COD and TP have also been significantly reduced. When the mixed liquor return ratio is reduced to 50%, the composite bacterial community system still maintains a high removal rate for pollutants, and at the same time realizes a 30% reduction in the system energy consumption, proving that the use of the composite bacterial community provided by the present invention helps to achieve more comprehensive and efficient removal of various forms of nitrogen pollutants.

[0035] The polyurethane sponge loaded with bacteria was collected, and the field emission scanning electron microscope (SEM) was used to observe the loading of the bacteria. The results are as Figure 1 shown. As can be seen from Figure 1 , the bacteria are evenly distributed on the polyurethane sponge. The bacteria grow and attach in the pores of the sponge, forming a stable biofilm structure, and there is no obvious shedding or aggregation on the surface, indicating that the bacteria can effectively colonize on the sponge surface and maintain their activity. These observation results prove that the polyurethane sponge as a carrier can provide sufficient surface area and microenvironment to support the good loading and growth of Pseudomonas sp. AD-1 and Alcaligenes sp. HO-1 bacterial communities.

[0036] Example 2

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

[0038] (1) Prepare simulated domestic sewage according to the influent indexes of the sewage treatment plant. The pollutant components and contents are COD 350 mg / L, TN 40 mg / L, NO 3 - -N 5 mg / L, NH 4 + -N 35 mg / L, and TP 3.2 mg / L. The experimental device is an SBR reactor (with an effective volume of 1.2 L). The operation cycle is set to 24 h, including 15 min for influent and effluent each, 16 h of aeration (DO is 3 mg / L), and 7.5 h of static settlement. The concentration of activated sludge in the system is about 300 mg / L.

[0039] (2) Start the experimental device and run it continuously. After the operation becomes stable, add 1% (v / v) Alcaligenes sp. HO-1 bacterial solution and 1% (v / v) Pseudomonas sp. AD-1 bacterial solution to the activated sludge treatment system, and adjust the HRT to 12 h, with 15 min for each of the influent and effluent, 8 h of aeration (DO is 3 mg / L), and 3.5 h of static settlement. Analyze the treatment efficiency of the system for pollutants. Centrifuge the water sample at 8000 r / min for 5 min, and filter it through a 0.22 μm filter membrane. Measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP), and chemical oxygen demand (COD) in the influent and effluent every day.

[0040] Analysis of test results: The SBR device operated for a total of 30 days. The pure activated sludge system reached the stable stage, and the effluent concentrations of TN, NH 4 + -N, and NO x — N (NO 3 — N and NO 2 — N) were 18.54 mg / L, 0.87 mg / L, and 16.86 mg / L respectively. After adding the mixed bacterial community, the effluent concentrations of TN, NH 4 + -N, and NO x — N (NO 3 — N and NO 2 — N) were 6.80 mg / L, 0.35 mg / L, and 3.16 mg / L respectively. After the HRT was reduced to 12 h, the effluent concentrations of TN, NH 4 + -N, and NO x — N (NO 3 — N and NO 2 — N) were 6.35 mg / L, 0.13 mg / L, and 3.58 mg / L respectively. The results show that the addition of the mixed bacterial community significantly improved the removal rate of TN, and the effluent concentration decreased from 18.54 mg / L to 6.80 mg / L, with a removal rate of 63.3%. At the same time, NO x —The concentration of N also decreased significantly by 13.7 mg / L, indicating a reduction in the accumulation of intermediate products and a significant improvement in the denitrification effect of the system. After the HRT was reduced to 12 h, the composite bacterial community system still maintained a high removal rate for pollutants. This shows that the mixed bacterial community of Alcaligenes sp. HO-1 and Pseudomonas sp. AD-1 can effectively improve the TN removal efficiency, inhibit the production of intermediate products. At the same time, the optimization of HRT has greatly improved the treatment efficiency of the system for pollutants, significantly accelerating the sewage treatment process, further proving the high efficiency of the coupling of the mixed bacterial community of Alcaligenes sp. HO-1 and Pseudomonas sp. AD-1.

[0041] Example 3

[0042] Application of a low-energy consumption denitrifying composite bacterial community in an activated sludge system, including the following steps:

[0043] (1) Prepare simulated domestic sewage according to the influent indexes of the sewage treatment plant. The components and contents of pollutants are COD 350 mg / L, TN 40 mg / L, NO 3 - -N 5 mg / L, NH 4 + -N 35 mg / L, TP 3.2 mg / L; The experimental device is an SBR reactor. The reaction cycle is set to 24 h, with 5 min of influent, 12 h of aeration, 11 h 25 min of static settlement, and 30 min of effluent. After each cycle, half of the liquid is discharged and then simulated wastewater is added to make up to 1.2 L. Use a BOD5 special water sample pretreatment aerator for aeration, and the air is introduced into the reactor through an 8 cm diameter aeration disc. The DO in the aeration stage of the reaction system is maintained at 4 mg / L, and 1 mg / L in the static settlement stage. The final concentration of activated sludge in the system is 3000 mg / L.

[0044] (2) Start up the device and run continuously. After the system operates stably, add 1% (v / v) Alcaligenes sp. HO-1 bacterial liquid and 1% (v / v) Pseudomonas sp. AD-1 bacterial liquid to the activated sludge treatment system. To increase the abundance of the denitrifying functional bacterial community, strengthen the bacterial liquid according to the above ratio every 7 d in the later stage. After the system containing the composite bacteria is stable, adjust the HRT to 12 h. Take the mixed liquid of the system after influent as the influent every day, and the supernatant of the system at the end of static settlement as the effluent. Centrifuge the water sample at 8000 r / min for 5 min and filter it through a 0.22 μm filter membrane. Measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP) and chemical oxygen demand (COD) in the influent and effluent every day.

[0045] Analysis of test results: The SBR device operated for 45 days in total. The pure activated sludge system reached the stable stage, and the effluent concentrations of TN, NH 4 + -N and NO x — N (NO 3 — N and NO 2 — N) were 16.99 mg / L, 0.75 mg / L and 12.28 mg / L respectively. After adding the mixed microbial community, the effluent concentrations of TN, NH 4 + -N and NO x — N (NO 3 — N and NO 2 — N) were 7.57 mg / L, 0.19 mg / L and 4.69 mg / L respectively. After the HRT was reduced to 12 h, the effluent concentrations of TN, NH 4 + -N and NO x — N (NO 3 — N and NO 2 — N) were 6.57 mg / L, 0.15 mg / L and 3.98 mg / L respectively. Through comparative analysis, the introduction of the mixed microbial community significantly improved the removal effect of TN, and the removal efficiency increased by 21.05%. The significant reduction of NO x — N proved that the nitrogen conversion process was optimized. After the HRT was reduced to 12 h, the composite microbial community system still maintained a high removal rate for pollutants, proving the high efficiency of the coupling of the mixed microbial community of Alcaligenes faecalis HO-1 and Pseudomonas sp. AD-1; the shortening of the HRT helped the reactor to treat more sewage per unit time, thereby improving the treatment capacity of the system.

[0046] Comparative Example 1

[0047] An application of a denitrifying microbial community in an activated sludge system, comprising the following steps:

[0048] (1) The influent was the actual wastewater from a municipal sewage treatment plant, and the pollutant components and contents were as follows: COD 280 mg / L, TN 30.0 mg / L, NO 3 - -N 1.5 mg / L, NH 4 +-N 25 mg / L, TP 2.5 mg / L. The sewage treatment system is an A2 / O device with an effective volume of 410 L. The volume ratio of the anaerobic tank: anoxic tank: aerobic tank is 1:1:3. The anaerobic tank has specifications of 460 mm × 400 mm × 500 mm. The sewage overflows to the anoxic tank from the top of the partition. There is a pipe at the bottom of the side of the anoxic tank connected to the bottom of the first aerobic tank, and then it enters the sedimentation tank through the overflow port at the end of the aerobic tank. The sedimentation tank is set as a radial flow sedimentation tank with dimensions of The anaerobic tank and anoxic tank use agitators to fully mix the sludge. There are aeration pipes at the bottom of the aerobic tank, and the aeration volume is precisely controlled through a flow meter. There is a water storage bucket at the front end of the reactor. Domestic sewage is pumped from the water storage device every day by a submersible pump to meet the treatment requirements.

[0049] (2) Start the experimental device and run continuously. After the experimental device starts and runs continuously, when the operation is stable, place 2 cm * 2 cm polyurethane sponge in the aerobic tank of AAO at a filling rate of 50%, and add 2% (v / v) of the bacterium Alcaligenes faecalis HO-1 bacterial solution to the active sludge treatment system with stable operation. Centrifuge the water sample at 8000 r / min for 5 min, and pass it through a 0.22 μm filter membrane. Measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP) and chemical oxygen demand (COD) in the influent and effluent water every day.

[0050] Analysis of test results: The AAO device operates for 80 days. The mixed liquor and sludge reflux ratios are both set at 200%. For the pure active sludge system, during the stable stage, the effluent concentrations of TN, NH 4 + -N and NO x — N are 20.38 mg / L, 15.70 mg / L and 1.95 mg / L respectively. The removal rates of TN and NH 4 + -N are 32.06% and 37.20% respectively. After adding Alcaligenes faecalis HO-1, during the stable stage, the effluent concentrations of TN, NH 4 + -N and NO x — N are 14.63 mg / L, 7.82 mg / L and 1.74 mg / L respectively. The removal rates of TN and NH 4 +-N removal rates were 51.23% and 68.72% respectively. Before and after the system construction, the average effluent concentration of TP in the system decreased from 0.97 mg / L to about 0.31 mg / L, and the average removal rate increased by 26.40%. The average effluent concentration of COD decreased by 24.8 mg / L. The results showed that Alcaligenes faecalis HO-1 with direct ammonia oxidation function could significantly improve the removal efficiency of TN and NH 4 + -N. The removal rates increased by 19.16% and 31.52% respectively, and it also showed good potential in improving the TN removal effect. However, for the NO x — already existing in water, the removal effect of N was relatively poor. The NO x — N concentration decreased from 1.93 mg / L to 1.74 mg / L, with a small decrease. This indicated that although the Alcaligenes community played a positive role in the total nitrogen removal, further optimization was still needed in the further conversion and removal of nitrite and nitrate.

[0051] Comparative Example 2

[0052] An application of a denitrifying flora in an activated sludge system, including the following steps:

[0053] (1) The influent is the actual wastewater from a municipal sewage treatment plant, and the pollutant components and contents are as follows: COD 280 mg / L, TN 30.0 mg / L, NO 3 - -N 1.5 mg / L, NH 4 + -N 25 mg / L, TP 2.5 mg / L. The sewage treatment system is an A2 / O device. The effective volume of this system is 410 L, and the volume ratio of the anaerobic tank: anoxic tank: aerobic tank is 1:1:3. The specification of the anaerobic tank is 460 mm × 400 mm × 500 mm. The sewage overflows to the anoxic tank from the top of the partition board. There is a pipeline at the bottom of the side of the anoxic tank connected to the bottom of the first aerobic tank, and then enters the sedimentation tank through the overflow port at the end of the aerobic tank. The sedimentation tank is set as a radial flow sedimentation tank, with dimensions of The anaerobic tank and the anoxic tank use stirrers to fully mix the sludge. There is an air diffuser at the bottom of the aerobic tank, and the aeration volume is accurately controlled through a flowmeter. There is a water storage bucket at the front end of the reactor, and domestic sewage is pumped from the water storage device every day through a submersible pump to meet the treatment requirements.

[0054] (2) Start the experimental device and run it continuously. After the experimental startup device runs continuously and stabilizes, place a 2 cm * 2 cm polyurethane sponge in the aerobic tank of the AAO at a filling rate of 50%, and add the Pseudomonas aeruginosa AD-1 bacterial solution at 2% (v / v) to the continuously operating activated sludge treatment system. Centrifuge the water sample at 8000 r / min for 5 min, and pass it through a 0.22 μm filter membrane. Measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP), and chemical oxygen demand (COD) in the influent and effluent water daily.

[0055] Analysis of test results: The reactor operated for a total of 60 days. When the pure activated sludge reaction device was operating stably, the effluent concentrations of TN, NH 4 + -N, and NO x — N were 13.34 mg / L, 6.58 mg / L, and 5.18 mg / L respectively, and the TN removal rate was 55.53%. After adding the Pseudomonas aeruginosa AD-1 bacterial solution with HN-AD function, the effluent concentrations of TN, NH 4 + -N, and NO x — N were 9.62 mg / L, 5.96 mg / L, and 0.24 mg / L respectively, and the TN removal rate was 67.9%. It can be seen that the strengthening effect of Pseudomonas aeruginosa AD-1 on TN removal in the activated sludge system is relatively limited. The TN removal efficiency was optimized by 12.4%, mainly due to the improvement of the NO x — N removal efficiency, while the improvement of the NH 4 + -N removal efficiency is limited, with only a 0.62 mg / L increase.

[0056] Comparative Example 3

[0057] An application of a denitrifying complex bacterial community in an activated sludge system, including the following steps:

[0058] (1) The influent is the actual wastewater from a certain municipal wastewater treatment plant, and the pollutant components and contents are as follows: COD 280 mg / L, TN 30.0 mg / L, NO 3 - -N 1.5 mg / L, NH 4 +-N at 25 mg / L, TP at 2.5 mg / L, the sewage treatment system is an A2 / O device. The effective volume of this system is 410 L. The volume ratio of the anaerobic tank: anoxic tank: aerobic tank is 1:1:3. Among them, the anaerobic tank has a specification of 460 mm × 400 mm × 500 mm. The sewage overflows to the anoxic tank from the top of the partition. There is a pipe at the bottom of the side of the anoxic tank connected to the bottom of the first aerobic tank, and then enters the sedimentation tank through the overflow port at the end of the aerobic tank. The sedimentation tank is set as a radial flow sedimentation tank with dimensions of The anaerobic tank and anoxic tank use stirrers to fully mix the sludge. There are aeration pipes at the bottom of the aerobic tank, and the aeration volume is precisely controlled through a flow meter. There is a water storage bucket at the front end of this reactor. Domestic sewage is pumped from the water storage device every day by a submersible pump to meet the treatment requirements.

[0059] (2) Start the experimental device and run continuously. After the experimental device starts and runs continuously, when the operation is stable, place a 2 cm * 2 cm polyurethane sponge in the aerobic tank of AAO at a filling rate of 50%. Add 1% (v / v) Alcaligenes faecalis 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 8000 r / min for 5 min, and filter it through a 0.22 μm filter membrane. Measure the concentrations of total nitrogen (TN), ammonia nitrogen (NH 4 + -N), nitrate nitrogen (NO 3 - -N), nitrite nitrogen (NO 2 - -N), total phosphorus (TP) and chemical oxygen demand (COD) in the influent and effluent every day.

[0060] Analysis of test results: The AAO device operates for a total of 60 days. The mixed liquor and sludge reflux ratios are both set at 200%. In the pure activated sludge system, the effluent concentrations of TN, NH 4 + -N and NO x — N (NO 3 — N and NO 2 — N) are 13.25 mg / L, 10.36 mg / L and 4.23 mg / L respectively. The removal rates of TN and NH 4 + -N are 55.83% and 58.56% respectively. The effluent concentrations of COD and TP are 14.27 mg / L and 0.68 mg / L respectively. After adding the mixed flora of Alcaligenes faecalis HO-1 and Alcaligenes faecalis CICC 22642, the effluent concentrations of TN, NH 4 + -N and NO x —The effluent concentrations of N are 8.55 mg / L, 5.09 mg / L, and 3.51 mg / L respectively, and the removal rates of TN and NH 4 + -N are 71.50% and 79.64% respectively. The effluent concentrations of COD and TP are 12.21 mg / L and 0.36 mg / L respectively, and the daily power consumption of the mixed liquor return pump is 1.06 kWh.

[0061] After reducing the mixed liquor return ratio from 200% to 50%, during the stable stage, the effluent concentrations of TN, NH 4 + -N and NO x — N are 11.32 mg / L, 7.28 mg / L, and 5.67 mg / L respectively, and the removal rates of TN and NH 4 + -N are 62.26% and 70.08% respectively. The effluent concentrations of COD and TP are 14.13 mg / L and 0.55 mg / L respectively, and the daily power consumption of the mixed liquor return pump is 0.76 kWh. It can be seen that when the return ratio is 200%, the TN removal efficiency is increased by 15.67%, mainly due to the 21.08% optimization of the NH 4 + -N removal performance. However, when the mixed liquor return ratio is reduced to 50%, the water quality deteriorates, indicating that the system of Alcaligenes faecalis HO-1 and Alcaligenes faecalis CICC22642 cannot adapt to this process condition.

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

[0063] Finally, it should be noted that the above embodiments do not limit the present invention in any form. For those skilled in the art, based on the present invention, some modifications and improvements can be made. Therefore, any modification or improvement made without departing from the spirit of the present invention falls within the scope of protection required by the present invention.

Claims

1. Application of a low-energy denitrification composite bacterial community in an activated sludge system, characterized in that: The denitrification composite bacterial community includes Alcaligenes HO-1 and Pseudomonas AD-1.

2. The use according to claim 1, characterized in that: The specific operation steps are: after the activated sludge system runs stably, the bacterial solution of Alcaligenes HO-1 and Pseudomonas AD-1 are directly added to the activated sludge system.

3. The use according to claim 2, characterized in that: The alcaligenes HO-1 bacterial liquid accounts for 0.5-2% of the volume of the sewage.

4. The use according to claim 2, characterized in that: The Pseudomonas AD-1 bacterial liquid accounts for 0.5-2% of the volume of the sewage.

5. The use according to claim 2, characterized in that: The number of live bacteria in the alcaligenes HO-1 bacterial solution is not less than 1.0×10 8 cfu / mL.

6. The use according to claim 2, characterized in that: The number of live bacteria in the Pseudomonas AD-1 bacterial solution is not less than 1.0×10 8 cfu / mL.

7. The use according to claim 1, characterized in that: The specific operation steps also include: after the activated sludge system runs stably, first fill the carrier, and then add the alcaligenes HO-1 bacterial solution and the Pseudomonas AD-1 bacterial solution into the activated sludge system.

8. The use according to claim 7, characterized in that: The carrier is selected from polyurethane sponge.

9. The use according to claim 7, characterized in that: The loading rate of the carrier is 30-50%.

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