Nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents

Abstract

This invention relates to the field of receiving water body remediation technology, and discloses a nitrogen and phosphorus removal treatment process for receiving water bodies based on a combined nitrifying microbial agent. The process includes the following steps: constructing a controlled-flow attachment treatment system in situ in the water body; spraying a combined microbial agent working solution to allow microorganisms to colonize and attach on non-woven fabric strips; aerating an aerobic baffle zone to oxidize ammonia nitrogen and degrade organic matter; replenishing alkalinity in situ through an ecological buffer dam to control pH; and allowing the water to enter an anoxic zone. A dual-effect polymer carrier housed in a permeable mesh bag releases volatile fatty acids to achieve nitrogen removal and releases magnesium ions that react with phosphate to form precipitates that are trapped in the micropores of the carrier. The carrier adsorbing solid phosphorus is periodically recovered and replaced. This invention solves the problems of weak nitrifying bacteria activity, incomplete phosphorus removal logic, and low agent utilization in receiving water bodies, achieving in-situ transformation and removal of pollutants, and possessing resistance to shock loads and long-term stability.

Description

Technical Field

[0001] This invention relates to the field of receiving water body remediation technology, specifically to a nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents. Background Technology

[0002] In in-situ remediation projects of receiving water bodies, enhancing the biochemical treatment capacity of the water body by adding microbial agents is the main direction of existing technologies. However, in the preparation of compound microbial agents, heterotrophic and autotrophic bacteria are usually produced by mixed fermentation. The heat generated by the fermentation pile during the fermentation process can reduce or deactivate the activity of autotrophic nitrifying bacteria with poor heat resistance, resulting in the final product failing to meet the design requirements for ammonia nitrogen conversion in practical applications.

[0003] Regarding the phosphorus removal process, the receiving water body has a unidirectional flow physical characteristic and lacks the spatial loop of alternating aerobic and anoxic conditions found in traditional wastewater treatment plants. After polyphosphate-accumulating bacteria release phosphorus in an anaerobic environment, the released phosphate ions migrate with the water flow and cannot be further biochemically absorbed in situ, making it difficult for phosphorus to be removed from the flowing water.

[0004] In terms of operational stability, the hydrodynamic conditions in open water bodies fluctuate significantly, and artificially added liquid carbon sources are easily diluted and lost with the water flow, failing to provide a stable electron donor for the denitrification process. Furthermore, due to the lack of effective flow guidance structures in the receiving water body, the residence time of water in the reaction zone is not fixed, easily leading to short-circuiting and reducing the overall biochemical degradation efficiency of pollutants. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents, which solves the problems of insufficient survival rate of nitrifying bacteria, solid-phase migration of phosphorus, and stability of carbon source supply in existing receiving water body remediation technologies.

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

[0007] This invention provides a nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents, comprising the following steps:

[0008] A flow-controlled attachment treatment system is constructed in the receiving water body, consisting of a pretreatment zone, an aerobic deflector zone, an ecological buffer dam, and an anoxic treatment zone.

[0009] Spray the combined bacterial agent working solution to allow microorganisms to colonize and form a film on the non-woven fabric strips in the anoxic treatment area;

[0010] Aeration and oxygenation are introduced into the aerobic baffle zone, utilizing microorganisms to degrade organic matter and oxidize ammonia nitrogen into nitrate nitrogen;

[0011] The water flows through the ecological buffer dam, where the alkalinity released in situ neutralizes the acidic substances, thus controlling the pH of the water flow.

[0012] Water flows into the anoxic treatment zone, which is in a low dissolved oxygen state. The anoxic treatment zone is equipped with a permeable mesh bag containing a dual-effect polymer carrier. The dual-effect polymer carrier hydrolyzes and releases volatile fatty acids. The denitrifying bacteria use the volatile fatty acids to reduce nitrate nitrogen to nitrogen gas to achieve denitrification.

[0013] At the same time, the dual-effect polymer carrier releases magnesium ions, which react with phosphate ions in the water to form precipitates and are trapped in the micropores of the dual-effect polymer carrier.

[0014] After continuous operation, the permeable mesh bag and dual-effect polymer carrier that adsorb solid phosphorus are recovered and replaced, the non-woven fabric strips are rinsed, phosphorus removal is completed and the process enters the next treatment cycle.

[0015] In the above technical solution, considering the inactivation effect of heat generated by materials during the heterotrophic fermentation stage on specific sensitive strains, this solution adopts a dual-track independent expansion culture process to prepare the combined bacterial agent working solution, which effectively maintains the biochemical activity of Nitrosomonas and Nitrobacterium.

[0016] To address the interference of fluctuating flow velocity in open water on substrate distribution, a dual-effect polymeric carrier with hydrolytic properties was applied in the anoxic treatment zone. This enabled in-situ supply of electron donors at the microbial attachment interface. Combined with the mineralization and crystallization effect of lightly calcined magnesium powder within the carrier, dissolved phosphorus was converted into a solid-phase product. Therefore, this invention achieves improved nitrogen and phosphorus removal efficiency, high carbon source utilization, pH self-balancing, and substantial removal of pollutants.

[0017] Preferably, the flow control attachment treatment system is constructed as follows:

[0018] An interception mesh with an aperture of 2cm to 5cm is installed in the pretreatment area to intercept impurities;

[0019] Multiple flexible guide walls with their bottoms hanging down to the riverbed are suspended in an alternating manner in the aerobic deflection zone, transforming the waterway into a deflection channel. Microporous aeration discs are evenly distributed at the bottom and connected to dissolved oxygen sensors.

[0020] In the ecological buffer dam, a structure wrapped with metal gabions is constructed, and the interior is filled with oyster shells and limestone with a particle size of 3cm to 8cm, and the mass ratio of oyster shells to limestone is 1:1 to 2:1.

[0021] A liftable support frame made of nylon mesh was installed in the hypoxic treatment zone, with multiple strands of material having a density greater than 1.1 g / cm³ tied to it. 3 The nonwoven fabric strips are used to pack the dual-effect polymer carrier into a water-permeable mesh bag with a pore size of 1-2 mm and set it in the middle and lower part of the liftable support through the nonwoven fabric strips.

[0022] By adopting the above technical solution, the present invention establishes a stable biochemical transformation space in the receiving water body, and the specific transformation mechanism is as follows:

[0023] Regarding the maintenance of the activity and synergistic degradation process of autotrophic nitrifying bacteria, this process avoids the killing effect of heterotrophic bacteria on autotrophic bacteria by independently preparing solid fermentation substrate and autotrophic nitrifying bacteria liquid during the preparation stage, thus ensuring the initial concentration of functional strains in the combined bacterial agent working solution.

[0024] When the bacterial solution enters the controlled-flow attachment treatment system, Nitrifying Monoclonal and Nitrifying Bacillus colonize in the aerobic baffle zone. Because the flexible guide wall extends the actual physical path of the water flow, the polluted substrate in the receiving water body can maintain sufficient contact time with the attached bacterial community. During this process, strains such as Bacillus subtilis degrade macromolecular organic matter, while autotrophic bacteria are responsible for the ammonia oxidation process.

[0025] Regarding the denitrification mechanism of in-situ precise carbon source supply, as nitrate nitrogen enters the anoxic treatment zone with the water flow, the stability of the denitrification process mainly depends on the continuity and effective concentration of the electron donor.

[0026] The dual-effect polymer carrier uses corn starch and polycaprolactone as its matrix and undergoes gradual depolymerization in an underwater environment via enzymes secreted by surface microorganisms. Because this release process occurs near the interface of the nonwoven fabric biofilm, the released volatile fatty acids are utilized in situ by denitrifying bacteria, reducing carbon source dilution and ineffective loss caused by water flow.

[0027] Since open water bodies cannot provide the phosphorus uptake conditions required by polyphosphate-accumulating bacteria, this scheme uses a chemical mineralization pathway to fix phosphorus.

[0028] Lightly calcined magnesium powder in the dual-effect polymer carrier is gradually exposed as the polymer skeleton hydrolyzes. When the magnesium powder comes into contact with water, magnesium ions are generated. Within the confined microporous space inside the carrier, the magnesium ions combine with diffused phosphate ions to form mineral precipitates. This transformation process is not affected by fluctuations in dissolved oxygen in the water.

[0029] The resulting minerals are encapsulated in a carrier structure, and phosphorus is removed by periodically replacing the carrier.

[0030] The pH regulation and microhabitat stabilization mechanism takes into account that aerobic nitrification releases protons and leads to aquatic acidification. The controlled-flow attached treatment system compensates for alkalinity through ecological buffer dams and carrier components. Oyster shells and limestone undergo a slight dissolution reaction in a slightly acidic environment, replenishing bicarbonate ions in the environment.

[0031] The solid-phase alkalinity replenishment mechanism, combined with the hydroxide ions generated from the hydration of lightly calcined magnesium powder, maintains the receiving water in a neutral range conducive to microbial metabolism. This self-balancing of pH, along with the physical regulation of hydraulic residence time by the flexible flow-guiding curtain wall, enhances the operational robustness of the entire purification process when facing flow surges.

[0032] This invention provides a nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents. It has the following beneficial effects:

[0033] 1. This invention, through the process of preparing solid fermentation substrate and autotrophic nitrifying bacteria liquid, ensures the initial concentration and biochemical activity of Nitrosomonas and Nitrifying Bacillus in the working solution of the combined bacterial agent, so that the controlled flow attachment treatment system can form a stable nitrifying bacteria community on the biofilm medium in the aerobic baffle zone at the initial stage of addition, thereby improving the conversion efficiency of ammonia nitrogen in the receiving water body.

[0034] 2. This invention utilizes lightly calcined magnesium powder in a dual-effect polymer carrier to release magnesium ions in the aquatic environment. These ions react with phosphate ions in the water within the carrier's micropores, forming an insoluble precipitate. This eliminates the dependence of traditional biological phosphorus removal processes on the spatial sequence of the receiving water body and the alternation of dissolved oxygen conditions, and avoids the defect of polyphosphate-accumulating bacteria releasing phosphorus without absorbing it in a single-flowing water body. By periodically replacing the carrier, phosphorus is substantially removed from the receiving water body, ensuring thorough phosphorus removal.

[0035] 3. This invention improves the carbon source utilization and operational stability of the controlled-flow attachment treatment system through the synergistic effect of a dual-effect polymer carrier and a flexible flow-guiding curtain wall. The interfacial hydrolysis of the carrier in the anoxic treatment zone releases volatile fatty acids in situ, allowing denitrifying bacteria attached to the non-woven fabric strips to directly absorb electron donors, reducing ineffective carbon source loss caused by diffusion with the water flow. Simultaneously, the flexible flow-guiding curtain wall extends the physical flow path, offsetting the impact of hydraulic load fluctuations, ensuring sufficient contact time between microorganisms and the contaminated substrate, and enhancing the impact resistance of the controlled-flow attachment treatment system in open water. Attached Figure Description

[0036] Figure 1 This is a top view of the flow control adhesion processing system of the present invention;

[0037] Figure 2 This is a radar chart showing the multi-indicator performance of the flow control attachment treatment system in the test example of this invention after 15 days of operation;

[0038] Figure 3 This is a radar chart showing the multi-indicator performance of the flow control attachment treatment system in the test example of this invention after 45 days of operation;

[0039] Figure 4 This is a diagram showing the carbon source release kinetics distribution in the anoxic treatment zone according to Example 1 of the present invention.

[0040] Figure 5 This is a diagram showing the carbon source release kinetics distribution in the anoxic treatment zone of Comparative Example 2 of the present invention;

[0041] Figure 6 This is a side view of the liftable support and permeable mesh bag of the flow control adhesion treatment system of the present invention.

[0042] The components include: 1. Interception net; 2. Flexible flow guide curtain wall; 3. Microporous aeration disc; 4. Dissolved oxygen sensor; 5. Ecological buffer dam; 6. Liftable support frame; and 7. Permeable mesh bag. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Preparation Examples 1-6:

[0045] Preparation Example 1:

[0046] This preparation example provides a method for preparing a dual-effect polymeric carrier, including the following steps:

[0047] Weigh the following raw materials in parts by weight: 42 parts corn starch, 32 parts polycaprolactone, 11 parts polyvinyl alcohol, 10 parts lightly calcined magnesium powder, 4 parts sodium alginate, and 1 part sodium bicarbonate.

[0048] Polycaprolactone was heated to 85°C to completely melt it. Then, polyvinyl alcohol, corn starch and lightly calcined magnesium powder were added in sequence and mixed at a constant temperature of 650 rpm for 25 minutes to obtain a paste-like blend.

[0049] When the temperature of the above paste-like blend naturally drops to 55°C, slowly add sodium alginate and sodium bicarbonate, and continue stirring for 15 minutes to ensure the material is evenly dispersed.

[0050] The stirred mixture was extruded into strips with a diameter of 8 mm using a screw extruder and then granulated. The granules were immediately immersed in a 3% calcium chloride solution for ion crosslinking and curing for 18 hours.

[0051] The solidified particles were removed, rinsed three times with deionized water, and dried in a 45°C oven for 30 hours to finally obtain a dual-effect polymer carrier.

[0052] Preparation Example 2:

[0053] This preparation example provides a method for preparing a dual-effect polymeric carrier, including the following steps:

[0054] Weigh the following raw materials in parts by weight: 45 parts corn starch, 30 parts polycaprolactone, 10 parts polyvinyl alcohol, 10 parts lightly calcined magnesium powder, 3 parts sodium alginate, and 2 parts sodium bicarbonate.

[0055] Polycaprolactone was heated to 80°C to completely melt it. Then, polyvinyl alcohol, corn starch and lightly calcined magnesium powder were added in sequence and mixed at a constant temperature of 500 rpm for 20 minutes to obtain a paste-like blend.

[0056] When the temperature of the above paste-like blend naturally drops to 50°C, slowly add sodium alginate and sodium bicarbonate, and continue stirring for 15 minutes to ensure the material is evenly dispersed.

[0057] The stirred mixture was extruded into strips with a diameter of 5 mm using a screw extruder and then granulated. The granules were immediately immersed in a 2% calcium chloride solution for ion crosslinking and curing for 12 hours.

[0058] The solidified particles were removed, rinsed twice with deionized water, and dried in a 40°C oven for 24 hours to obtain a dual-effect polymer carrier.

[0059] Preparation Example 3:

[0060] This preparation example provides a method for preparing a dual-effect polymeric carrier, including the following steps:

[0061] Weigh the following raw materials in parts by weight: 44 parts corn starch, 33 parts polycaprolactone, 11 parts polyvinyl alcohol, 8 parts lightly calcined magnesium powder, 3 parts sodium alginate, and 1 part sodium bicarbonate.

[0062] Polycaprolactone was heated to 90°C to completely melt it. Then, polyvinyl alcohol, corn starch and lightly calcined magnesium powder were added in sequence and mixed at a constant temperature of 800 rpm for 30 minutes to obtain a paste-like blend.

[0063] When the temperature of the above paste-like blend naturally drops to 60°C, slowly add sodium alginate and sodium bicarbonate, and continue stirring for 20 minutes to ensure the material is evenly dispersed.

[0064] The stirred mixture was extruded into strips with a diameter of 10 mm using a screw extruder and then granulated. The granules were immediately immersed in a 4% calcium chloride solution for ion crosslinking and curing for 24 hours.

[0065] The solidified particles were removed, rinsed three times with deionized water, and dried in a 50°C oven for 36 hours to finally obtain a dual-effect polymer carrier.

[0066] Preparation Example 4:

[0067] This preparation example provides a method for preparing a combined bacterial agent working solution, including the following steps:

[0068] Preparation of solid fermentation substrate: 75 wt% chicken manure dry matter and 25 wt% rice husk powder were evenly mixed as the fermentation substrate; 2 wt% of the total mass of the fermentation substrate was inoculated with the first fermentation powder (containing Bacillus subtilis, Saccharomyces cerevisiae, and Streptomyces actinomycetes, with each species having an effective viable count of 100000%). Adjust the moisture content of the material to 58% and carry out aerobic stacking fermentation at a temperature of 62℃ for 2.5 days;

[0069] Subsequently, a second fermentation powder (containing Bifidobacterium thermophilum, Bacillus compostii, and River Streamer bacillus, with an effective viable count of 2×10⁻⁶ for each strain) was added at 6 wt% of the initial fermentation substrate dry weight, dissolved in 40°C warm water. 8 The material moisture content was adjusted to 72% (CFU / g), and fermentation continued for 6 days at 68℃. After fermentation, the material was cooled and dried to obtain solid fermentation substrate.

[0070] Preparation of autotrophic nitrifying bacteria broth: In an independent liquid fermenter, using inorganic ammonium salt as the sole nitrogen source (pH 7.8, temperature 30℃), *Nitrosomonas* and *Nitrobacterium* were independently cultured. After fermentation, the final effective viable count was [number missing]. Autotrophic nitrifying bacteria solution.

[0071] Preparation of the combined microbial agent working solution: Take solid fermentation substrate (85 wt% of the total mixture mass) and autotrophic nitrifying bacteria solution (15 wt% of the total mixture mass) and mix them at room temperature; then add brown sugar at 1.5 wt% of the total mixture mass and add water at 9 times the mass of the mixture. Let it stand at 22℃ for 2 hours to activate, and finally obtain a combined microbial agent working solution with a mass fraction of 10%.

[0072] Preparation Example 5:

[0073] This preparation example provides a method for preparing a combined bacterial agent working solution, including the following steps:

[0074] Preparation of solid fermentation substrate: 80 wt% chicken manure dry matter and 20 wt% rice husk powder were evenly mixed as fermentation substrate; 1 wt% of the total mass of fermentation substrate was inoculated with first fermentation powder (containing Bacillus subtilis, Saccharomyces cerevisiae, and Streptomyces actinomycetes, with each species having an effective viable count of 5 × 10⁻⁶). 7 (CFU / g), adjust the moisture content of the material to 55%, and carry out aerobic stacking fermentation at a temperature of 65℃ for 2 days;

[0075] Subsequently, a second fermentation powder (containing Bifidobacterium thermophilum, Bacillus compostii, and River Streamer bacillus, with an effective viable count of each strain) was added at 5 wt% of the initial fermentation substrate dry weight, dissolved in 40°C warm water. The moisture content of the material was adjusted to 70%, and fermentation continued for 5 days at a temperature of 70℃. After fermentation, the material was cooled and dried to obtain solid fermentation substrate.

[0076] Preparation of autotrophic nitrifying bacteria broth: In an independent liquid fermenter, using inorganic ammonium salt as the sole nitrogen source (pH 8.0, temperature 32℃), *Nitrosomonas* and *Nitrobacterium* were independently cultured. After fermentation, the final effective viable count was 5 × 10⁻⁶. 8 Autotrophic nitrifying bacteria solution with CFU / mL.

[0077] Preparation of the combined microbial agent working solution: Take solid fermentation substrate (accounting for 90 wt% of the total mixture mass) and autotrophic nitrifying bacteria solution (accounting for 10 wt% of the total mixture mass) and mix them at room temperature; then add brown sugar at 1.8 wt% of the total mixture mass and add water at 11.5 times the mass of the mixture. Let it stand at 25℃ for 2.5 hours to activate it, and finally obtain a combined microbial agent working solution with a mass fraction of 8%.

[0078] Preparation Example 6:

[0079] This preparation example provides a method for preparing a combined bacterial agent working solution, including the following steps:

[0080] Preparation of solid fermentation substrate: 70 wt% chicken manure dry matter and 30 wt% rice husk powder were evenly mixed as the fermentation substrate; 3 wt% of the total mass of the fermentation substrate was inoculated with the first fermentation powder (containing Bacillus subtilis, Saccharomyces cerevisiae, and Streptomyces actinomycetes, with each species having an effective viable count of 100000%). Adjust the moisture content of the material to 60%, and carry out aerobic stacking fermentation for 3 days at a temperature of 60℃.

[0081] Subsequently, a second fermentation powder (containing Bifidobacterium thermophilum, Bacillus compostii, and River Streamer bacillus, with an effective viable count of 1×10⁻⁶ for each strain) was added at 8 wt% of the initial fermentation substrate dry weight, dissolved in 40°C warm water. 8 The material moisture content was adjusted to 75% (CFU / g), and fermentation continued for 8 days at 65℃. After fermentation, the material was cooled and dried to obtain solid fermentation substrate.

[0082] Preparation of autotrophic nitrifying bacteria broth: In an independent liquid fermenter, using inorganic ammonium salt as the sole nitrogen source (pH 7.5, temperature 28℃), *Nitrosomonas* and *Nitrobacterium* were independently cultured. After fermentation, the final effective viable count was 1×10⁻⁶. 8 Autotrophic nitrifying bacteria solution with CFU / mL.

[0083] Preparation of the combined microbial agent working solution: Take solid fermentation substrate (80 wt% of the total mixture mass) and autotrophic nitrifying bacteria solution (20 wt% of the total mixture mass) and mix them at room temperature; then add brown sugar at 1.2 wt% of the total mixture mass and add water at 7.3 times the mass of the mixture. Let it stand at 20℃ for 1.5 hours to activate it, and finally obtain a combined microbial agent working solution with a mass fraction of 12%.

[0084] Examples 1-3:

[0085] Example 1:

[0086] This embodiment provides a nitrogen and phosphorus removal process for receiving water bodies based on combined nitrifying microbial agents.

[0087] In the controlled-flow adhesion treatment system constructed in this embodiment, the combined bacterial agent working solution prepared according to Preparation Example 4 was taken and evenly sprayed at a dosage concentration of 30 mg / L of the total volume of the aerobic baffle zone and the anoxic treatment zone in the receiving water body. The addition was carried out continuously for 3 days, so that microorganisms could colonize and attach to the various functional areas of the controlled-flow adhesion treatment system and the non-woven fabric strips.

[0088] The microporous aeration disc 3 is activated, and the dissolved oxygen in the aerobic baffle zone is stably controlled at 7.0 mg / L via the dissolved oxygen sensor 4. The arrangement of the flexible guide wall 2 is adjusted to achieve a hydraulic retention time of 5 hours. Within this zone, Bacillus subtilis degrades organic matter in the water, while Nitrifying Monoclonal and Nitrifying Bacillus oxidize ammonia nitrogen in the water into nitrate nitrogen, thus carrying out aerobic nitrification.

[0089] After aerobic treatment, the water flows naturally over the ecological buffer dam 5. The oyster shells and limestone inside the dam dissolve slightly in the slightly acidic water and release alkalinity, effectively neutralizing the acidic substances produced in the previous stage. This keeps the pH of the effluent at 7.2, achieving passive buffering of pH in the controlled flow attachment treatment system.

[0090] Water continues to seep into the anoxic treatment zone, controlling the dissolved oxygen level in this area to be below 0.4 mg / L. The dual-effect polymer carrier prepared according to Preparation Example 1, suspended in this zone, slowly releases volatile fatty acids under hydrolysis. The denitrifying bacteria attached to the nonwoven fabric strips use these fatty acids as electron donors to reduce nitrate nitrogen in the water to nitrogen gas, which then dissipates. Simultaneously, the dual-effect polymer carrier exposes its internal lightly calcined magnesium powder and releases magnesium ions, which react with phosphate ions in the water in an in-situ mineralization reaction to form insoluble precipitates. These precipitates are trapped in the micropores inside the dual-effect polymer carrier, completing the anoxic denitrification and chemical phosphorus locking process.

[0091] After the controlled-flow attachment treatment system has been running continuously for 30 days, the nylon netting in the anoxic treatment zone is lifted out of the water using a lifting device. The permeable netting bag 7, which is saturated with solid phosphorus, is then removed and recycled. Subsequently, the permeable netting bag 7 is replaced with a new dual-effect polymer carrier prepared according to Preparation Example 1. At the same time, a high-pressure water gun is used to wash the non-woven fabric strips to remove the aged biofilm on the surface. After washing, the nylon netting is submerged back into the water to enter the next treatment cycle, ultimately achieving the complete removal of phosphorus and pollutant substrates from the controlled-flow attachment treatment system.

[0092] Example 2:

[0093] This embodiment provides a nitrogen and phosphorus removal process for receiving water bodies based on combined nitrifying microbial agents.

[0094] In the controlled-flow adhesion treatment system constructed in this embodiment, the combined bacterial agent working solution prepared according to Preparation Example 5 was taken and uniformly sprayed at a dosage concentration of 40 mg / L of the total volume of the aerobic baffle zone and the anoxic treatment zone in the receiving water body. The addition was carried out continuously for 4 days, so that microorganisms could colonize and attach to the various functional areas of the controlled-flow adhesion treatment system and the non-woven fabric strips.

[0095] The microporous aeration disc 3 is activated, and the dissolved oxygen in the aerobic baffle zone is stably controlled at 6.0 mg / L via the dissolved oxygen sensor 4. The arrangement of the flexible guide curtain wall 2 is adjusted to achieve a hydraulic retention time of 4 hours. Within this area, Bacillus subtilis degrades organic matter in the water, while Nitrifying Monoclonal and Nitrifying Bacillus oxidize ammonia nitrogen in the water into nitrate nitrogen, carrying out an aerobic nitrification reaction.

[0096] After aerobic treatment, the water flows naturally over the ecological buffer dam 5. The oyster shells and limestone inside the dam dissolve slightly in the slightly acidic water and release alkalinity, effectively neutralizing the acidic substances produced in the previous stage, so that the pH of the effluent is maintained at 7.0, thus achieving passive buffering of pH in the controlled flow attachment treatment system.

[0097] Water continues to seep into the anoxic treatment zone, controlling the dissolved oxygen level in this area to be below 0.3 mg / L. The dual-effect polymer carrier prepared according to Preparation Example 2, suspended in this zone, slowly releases volatile fatty acids through hydrolysis. Denitrifying bacteria attached to the nonwoven fabric strips use these fatty acids as electron donors to reduce nitrate nitrogen in the water to nitrogen gas, which then dissipates. Simultaneously, the dual-effect polymer carrier exposes its internal lightly calcined magnesium powder and releases magnesium ions, which react with phosphate ions in the water in an in-situ mineralization reaction to form insoluble precipitates. These precipitates are trapped in the micropores within the dual-effect polymer carrier, completing the anoxic denitrification and chemical phosphorus locking process.

[0098] After the controlled-flow attachment treatment system has been running continuously for 35 days, the nylon netting in the anoxic treatment zone is lifted out of the water using a lifting device. The permeable netting bag 7, which is saturated with solid phosphorus, is then removed and recycled. Subsequently, the permeable netting bag 7 is replaced with a new dual-effect polymer carrier prepared according to Preparation Example 2. At the same time, a high-pressure water gun is used to wash the non-woven fabric strips to remove the aged biofilm on the surface. After washing, the nylon netting is submerged back into the water to enter the next treatment cycle, ultimately achieving the complete removal of phosphorus and pollutant substrates from the controlled-flow attachment treatment system.

[0099] Example 3:

[0100] This embodiment provides a nitrogen and phosphorus removal process for receiving water bodies based on combined nitrifying microbial agents.

[0101] In the controlled-flow adhesion treatment system constructed in this embodiment, the combined bacterial agent working solution prepared according to Preparation Example 6 was taken and uniformly sprayed at a dosage concentration of 50 mg / L of the total volume of the aerobic baffle zone and the anoxic treatment zone in the receiving water body. The addition was carried out continuously for 5 days, so that microorganisms could colonize and attach to the various functional areas of the controlled-flow adhesion treatment system and the non-woven fabric strips.

[0102] The microporous aeration disc 3 is activated, and in conjunction with the dissolved oxygen sensor 4, the dissolved oxygen in the aerobic baffle zone is stably controlled at 8.0 mg / L. The arrangement of the flexible guide wall 2 is adjusted to achieve a hydraulic retention time of 6 hours. Within this area, Bacillus subtilis degrades organic matter in the water, while Nitrifying Monoclonal and Nitrifying Bacillus oxidize ammonia nitrogen in the water into nitrate nitrogen, thus carrying out an aerobic nitrification reaction.

[0103] After aerobic treatment, the water flows naturally over the ecological buffer dam 5. The oyster shells and limestone inside the dam dissolve slightly in the slightly acidic water and release alkalinity, effectively neutralizing the acidic substances produced in the previous stage. This keeps the pH of the effluent at 7.5, achieving passive buffering of pH in the controlled flow attachment treatment system.

[0104] Water continues to seep into the anoxic treatment zone, controlling the dissolved oxygen level in this area to be below 0.5 mg / L. The dual-effect polymer carrier prepared according to Preparation Example 3, suspended in this zone, slowly releases volatile fatty acids under hydrolysis. The denitrifying bacteria attached to the nonwoven fabric strips use these fatty acids as electron donors to reduce nitrate nitrogen in the water to nitrogen gas, which then dissipates. Simultaneously, the dual-effect polymer carrier exposes its internal lightly calcined magnesium powder and releases magnesium ions, which react with phosphate ions in the water in an in-situ mineralization reaction to form insoluble precipitates. These precipitates are trapped in the micropores inside the dual-effect polymer carrier, completing the anoxic denitrification and chemical phosphorus locking process.

[0105] After the controlled-flow attachment treatment system has been running continuously for 45 days, the nylon netting in the anoxic treatment zone is lifted out of the water using a lifting device. The permeable netting bag 7, which is saturated with solid phosphorus, is then removed and recycled. Subsequently, the permeable netting bag 7 is replaced with a new dual-effect polymer carrier prepared according to Preparation Example 3. At the same time, a high-pressure water gun is used to wash the non-woven fabric strips to remove the aged biofilm on the surface. After washing, the nylon netting is submerged back into the water to enter the next treatment cycle, ultimately achieving the complete removal of phosphorus and pollutant substrates from the controlled-flow attachment treatment system.

[0106] Comparative Examples 1-3:

[0107] Comparative Example 1:

[0108] Compared with Example 1, the difference is that in the preparation of the combined bacterial agent working solution, the dual-track independent preparation process was not adopted. Instead, the first and second fermentation powders required for the solid fermentation substrate were mixed with the Nitrifying Monoclonal and Nitrifying Bacillus in the autotrophic nitrifying bacteria liquid and then uniformly fermented at 60°C to 70°C according to the process of preparing the solid fermentation substrate in Example 4. All other aspects were the same.

[0109] Comparative Example 2:

[0110] Compared with Example 1, the difference is that the dual-effect polymer carrier is not used in the anoxic treatment zone, but is replaced by a common carrier without lightly calcined magnesium powder, and an equivalent amount of liquid glucose solution is directly sprayed into the anoxic treatment zone at regular intervals every day, while the rest are the same.

[0111] Comparative Example 3:

[0112] Compared with Example 1, the difference is that in the construction of the impact-resistant flow control attachment treatment system, the flexible flow guide curtain wall 2 and the ecological buffer dam 5 are not set up (i.e., oyster shells and limestone are not filled), only the aeration equipment and the end support are retained, and the rest are the same.

[0113] Test Examples 1-4:

[0114] Test Example 1:

[0115] This test case verifies the transformation and removal of pollutants in each functional area of ​​the controlled flow adhesion treatment system.

[0116] The flow control attachment processing system constructed in Example 1 was selected as the test object. The system has been running stably for more than 20 days.

[0117] Along the direction of water flow within the system, four fixed water quality sampling points are set up in sequence: the inlet of the pretreatment zone, the middle of the aerobic deflector zone, the outlet of the ecological buffer dam 5, and the end of the anoxic treatment zone.

[0118] Water samples were collected from the four nodes at a depth of 0.5 meters below the water surface using a constant-depth sampler. Sampling was conducted continuously for 3 days, with samples taken twice a day, once in the morning and once in the evening. Equal volumes of samples from the same node were mixed together to form the daily water sample for that node.

[0119] On-site, a portable multi-parameter water quality analyzer was used to measure pH and dissolved oxygen concentration; in the laboratory, Nessler's reagent spectrophotometry was used to measure ammonia nitrogen concentration, ultraviolet spectrophotometry was used to measure nitrate nitrogen and total nitrogen concentration, and ammonium molybdate spectrophotometry was used to measure total phosphorus concentration.

[0120] Record the measured values ​​of water quality indicators at each spatial node and calculate the average concentration.

[0121] Table 1. Changes in water quality indicators at various spatial nodes along the system in Example 1

[0122] Sampling space nodes Ammonia nitrogen (mg / L) Nitrate nitrogen (mg / L) Total nitrogen (mg / L) Total phosphorus (mg / L) Dissolved oxygen (mg / L) pH level Pretreatment zone inlet end 18.23 0.84 22.15 2.61 1.12 7.34 Middle of the aerobic baffle zone 2.15 14.88 20.31 2.38 6.85 6.27 Ecological buffer dam 5 outlet end 1.92 15.11 19.86 2.21 4.63 7.21 End of hypoxia treatment zone 1.76 1.35 3.94 0.42 0.38 7.45

[0123] See appendix Figure 1 and attached Figure 6 , attached Figure 1 The system showcases a pretreatment zone (equipped with an intercepting net 1), an aerobic baffle zone (equipped with a flexible flow guide wall 2, microporous aeration discs 3, and dissolved oxygen sensors 4), an ecological buffer dam 5 (made of metal gabions and filled with oyster shells and limestone), and an anoxic treatment zone (a liftable support 6 made of nylon mesh, with multiple non-woven fabric strips tied to the support 6, and permeable mesh bags 7 installed in the lower middle part of the support 6 via the non-woven fabric strips), where the water flow direction is from left to right; Figure 6 The relative positional relationship between the permeable mesh bag 7 and the liftable support 6 is shown.

[0124] Based on the measured data in Table 1, the water body exhibits relatively obvious biochemical transformation characteristics as it flows through the various functional zones of the system. The ammonia nitrogen concentration at the inlet is 18.23 mg / L, which decreases to 2.15 mg / L after entering the aerobic baffle zone, while the nitrate nitrogen concentration increases to 14.88 mg / L.

[0125] In conventional natural water body restoration projects, such high-load ammonia oxidation processes often consume large amounts of environmental alkalinity and cause pH imbalances. This was confirmed by measured data from the aerobic baffle zone, where the water's pH level dropped significantly to 6.27. However, after the water flowed past ecological buffer dam 5, the pH level rebounded to 7.21, indicating that the alkali release mechanism established by the limestone and oyster shells effectively prevented the subsequent nitrification process from being inhibited due to a sudden drop in pH.

[0126] This strategy of achieving in-situ acid-base compensation through structures creates stable influent conditions for subsequent nitrogen and phosphorus removal.

[0127] Observation of the data at the end of the anoxic treatment zone revealed that, in an environment where dissolved oxygen was only 0.38 mg / L, the concentrations of nitrate nitrogen and total nitrogen dropped to 1.35 mg / L and 3.94 mg / L, respectively.

[0128] Based on previous studies on the easy loss of denitrifying carbon sources with water flow during open water remediation, the denitrification efficiency here confirms that the dual-effect polymer carrier can depolymerize in an anaerobic microenvironment and continuously provide the small molecule carbon source required to drive denitrification.

[0129] During the denitrification process, the total phosphorus concentration decreased from the initial 2.61 mg / L to 0.42 mg / L. Unlike traditional unidirectional flow-channel biological phosphorus removal processes that often face the problem of secondary phosphorus release by microorganisms, this scheme relies on magnesium ions released from the hydration of lightly calcined magnesium powder inside the carrier for phosphorus removal. Metal cations and phosphate ions in the water undergo chemical precipitation in the spatial intersection area, retaining phosphorus in the pores in the form of inorganic minerals, thus achieving simultaneous fixation and removal of pollutants without changing the hydrodynamic conditions.

[0130] Test Example 2:

[0131] This test case verifies the advantages and long-term stability of the controlled flow attachment treatment system in nitrogen and phosphorus removal during the remediation of receiving water bodies by conducting parallel comparative experiments on Examples 1-3 and Comparative Examples 1-3.

[0132] Six sets of flow control and attachment treatment systems simulating receiving water channels were constructed in parallel under outdoor conditions to ensure that the hydraulic load and physical dimensions of each set of channels were completely consistent. The hydraulic residence time of each set was uniformly adjusted to 5 hours using a flexible flow guide curtain wall 2.

[0133] Each system was debugged according to the process parameters and material ratios of Examples 1-3 and Comparative Examples 1-3, respectively. The Example groups incorporated a combined bacterial agent working solution and a dual-effect polymer carrier; the Comparative groups controlled variables regarding the bacterial agent preparation method, carrier composition, and pH buffering facilities to observe the impact of single factors on system performance. Artificially prepared wastewater was used for the experiments, with the concentrations of ammonia nitrogen, total nitrogen, and total phosphorus limited to 15.5-20.2 mg / L, 20.1-25.4 mg / L, and 2.2-2.8 mg / L, respectively, to simulate the actual levels of the receiving water body under different pollution loads. The controlled-flow attachment treatment system operated continuously for 45 days, with water samples collected from the end discharge of each system on days 7, 15, 30, and 45.

[0134] The removal rates of total nitrogen, total phosphorus, and ammonia nitrogen in water samples were determined using standard analytical methods. The pH dynamics of the aerobic baffle zone were recorded in real time, and the data from each group were finally summarized for comprehensive evaluation.

[0135] Table 2. Comparison of the purification efficiency of receiving water bodies between the examples and comparative examples.

[0136]

[0137] See appendix Figure 2 and attached Figure 3 , attached Figure 2 The document presents a performance comparison of Example 1, Comparative Example 1, and Comparative Example 2 after 15 days of operation, regarding total nitrogen removal rate, total phosphorus removal rate, ammonia nitrogen removal rate, and pH stability. (Appendix) Figure 3 The diagram shows the attenuation and maintenance of key purification indicators after 45 days of long-term operation of Example 1, Comparative Example 1, and Comparative Example 2, to demonstrate the long-term stability of the process of the present invention.

[0138] The measured data recorded in Table 2 and the attached... Figure 2 and attached Figure 3 Analysis of the information shows that the removal rates of total nitrogen and total phosphorus in each embodiment group remained in a high and stable range during the 45-day operation period. This performance indicates that the various biochemical processes within the controlled flow adhesion treatment system are closely integrated. In particular, a comparison with the data of Comparative Example 1 reveals that its ammonia nitrogen removal rate after 45 days of operation was only 25.14%, far lower than the 86.47% of Example 1.

[0139] Because Comparative Example 1 did not employ a dual-track separation process during the preparation of the microbial inoculant, a large number of *Nitrosomonas* and *Nitrobacterium* were inactivated during the high-temperature fermentation stage. This resulted in the loss of the core driving force for converting ammonia nitrogen to nitrate nitrogen in the aerobic baffle zone. Without the upstream nitrification products, the downstream anoxic denitrification process naturally could not proceed normally, confirming the necessity of a dual-track preparation process for maintaining the activity of *Nitrosomonas* and *Nitrobacterium*.

[0140] Regarding the phosphorus removal logic, the effluent data of Comparative Example 2 showed a regular anomaly. By the 45th day of operation, the total phosphorus removal rate of Comparative Example 2 was -25.41%, indicating that the phosphorus concentration in the effluent had exceeded that in the influent.

[0141] The phenomenon of phosphorus levels increasing instead of decreasing is common in open water body treatment, mainly because Comparative Example 2 relied on the traditional biological phosphorus removal logic of polyphosphate-accumulating bacteria in the anoxic treatment zone. The receiving water body is a unidirectional flow open system. After absorbing carbon sources in the anoxic section, polyphosphate-accumulating bacteria undergo anaerobic phosphorus release, and the released phosphate is directly discharged with the water flow. The downstream section of the controlled-flow attachment treatment system lacks the necessary aerobic phosphorus uptake stage to complete phosphorus recovery.

[0142] In contrast, Example 1 introduced lightly calcined magnesium powder into a dual-effect polymer carrier and used a chemical mineralization phosphorus-locking pathway to fix phosphorus in the carrier pores in the form of precipitation, thereby achieving effective phosphorus removal under the condition of limited biochemical spatial sequence.

[0143] Furthermore, the pH stability of the controlled-flow attachment treatment system is crucial for maintaining long-term purification capabilities. In Comparative Example 3, due to the absence of an ecological buffer dam 5, the pH value of its aerobic zone decreased from an initial 6.15 to 5.84 after 45 days.

[0144] In actual river management processes, if the hydrogen ions produced by nitrification are not neutralized in time, the acidic environment will inhibit the metabolic rate of Nitrosomonas and Nitrobacterium.

[0145] Each embodiment utilizes the slightly soluble properties of oyster shells and limestone within the ecological buffer dam 5 to tightly integrate passive alkalinity compensation with water flow deflection, ensuring that the system pH value is always maintained in a neutral range above 7.0.

[0146] Based on long-term monitoring results, it can be observed that this solution utilizes a flow-controlled attachment treatment system to coordinate the biochemical conflicts between various functional components, demonstrating better process robustness in response to water quality fluctuations and ensuring the long-term effectiveness of the remediation process.

[0147] Test Example 3:

[0148] This test case aims to evaluate the stability of the flow-controlled attachment treatment system in the face of hydraulic load fluctuations and long-term operation, mainly considering the recovery of biochemical performance and hardware carrier wear under extreme conditions.

[0149] The flow control attachment treatment system constructed in Examples 1-3 was selected as the monitoring object. During the 45-day operation cycle, the pH was sampled and measured daily in the aerobic baffle zone to evaluate the sustainability of alkalinity compensation of lightly calcined magnesium powder in the ecological buffer dam 5 and the dual-effect polymer carrier.

[0150] A hydraulic load impact test was conducted on the 25th day of operation. A variable frequency inlet pump was used to instantly increase the inlet flow rate of each system from the rated flow rate to 2.5 times, simulating a surge in rainfall runoff. Under a continuous 24-hour impact load, the ammonia nitrogen concentration of the effluent from the aerobic baffle zone was measured every 4 hours to evaluate the effect of the flexible guide wall 2 on maintaining biochemical reaction efficiency while shortening the hydraulic residence time.

[0151] After the impact test, the influent flow rate was restored to the rated value, and the system continued to operate while monitoring the recovery of various indicators.

[0152] At the end of the 45-day cycle, all permeable mesh bags 7 in the anoxic treatment zone were recovered using the equipment, and the remaining dual-effect polymer carriers inside were removed. After rinsing with clean water to remove surface biofilm and impurities, they were placed in an oven and dried at 105°C to constant weight.

[0153] The initial and final mass of the carrier inside each permeable mesh bag 7 were recorded to calculate the mass loss rate; the recovered residual carrier was subjected to strong acid digestion treatment, and the total phosphorus content immobilized inside was quantitatively analyzed by the molybdenum blue colorimetric method to verify the physical interception effect of pollutants.

[0154] Table 3. Summary of Long-Term Stability and Shock Resistance Test Data of the System in the Example Example

[0155]

[0156] According to the monitoring data in Table 3, during the 45-day operation of Examples 1 and 3, the pH value of the aerobic baffle zone remained above 7.0. Although the pH value of Example 2 dropped to 6.88 in the later stage of operation, the overall water quality remained close to neutral. In actual engineering, the continuous high-intensity ammonia oxidation process consumes a large amount of environmental alkalinity. If the buffering capacity of the raw water is insufficient, it can easily lead to water acidification and, in turn, inhibit the activity of Nitrifying Monotrophus and Nitrifying Bacillus. The above measured data show that the oyster shells in the ecological buffer dam 5 and the lightly calcined magnesium powder in the carrier can provide continuous alkalinity compensation through slow dissolution, maintaining the necessary acid-base environment for nitrogen and phosphorus removal in the later stage of the system without relying on artificial chemical addition.

[0157] This stable microenvironment provides the foundation for the system to withstand external flow surges. In an extreme test facing 2.5 times the hydraulic load, the ammonia nitrogen conversion rate in Example 1 decreased from 87.4% to 78.3%. Faced with a sudden surge in water volume, conventional plug flow reactors typically experience a significant drop in treatment efficiency due to biofilm shedding or sludge loss.

[0158] In this design, the flexible flow-guiding curtain wall 2 constructs a meandering flow channel, extending the actual water flow trajectory. This forces a shorter hydraulic residence time due to the increased flow rate, but the Nitrifying Monoclonal and Nitrifying Bacillus bacteria attached to the curtain wall surface can still maintain a relatively sufficient contact and reaction time with the pollutants. The rapid recovery of the conversion rate after the test reflects the strong adhesion of the combined nitrifying microbial agent, indicating that the overall community structure was not substantially damaged by the violent water flow.

[0159] From the perspective of long-term material consumption, the physical loss and chemical retention capacity of the carrier are also key factors in evaluating process reliability. After 45 days of soaking and biodegradation, the mass loss rate of the dual-effect polymer carriers in each example ranged from 16.5% to 21.4%. This relatively gradual degradation rate ensured the uniform and continuous release of the small-molecule carbon source required for the denitrification process.

[0160] Meanwhile, solid phosphorus levels of up to 45.8 mg / g were detected in the recovered residual carrier. Magnesium ions released from the hydration of lightly calcined magnesium powder in the aquatic environment undergo mineralization and crystallization reactions with phosphate ions in the denitrification zone. Phosphorus is encapsulated in the micropores of the carrier as inorganic salts; this solid-phase enrichment method based on chemical precipitation is more stable than simple surface adsorption. Finally, total phosphorus is removed from the receiving water body by periodically lifting and replacing these phosphorus-rich carriers.

[0161] Test Example 4

[0162] This test case examines the carbon source supply kinetics of a controlled-flow attachment treatment system in an oxygen-deficient environment, comparing the differences in substrate utilization efficiency and release stability between solid-phase carrier slow release and direct liquid-phase addition.

[0163] Example 1 and Comparative Example 2, both in a stable operating period, were selected as the monitoring subjects. In Example 1, a dual-effect polymer carrier was suspended inside the anoxic treatment zone, while in Comparative Example 2, liquid glucose solution was manually added to the anoxic treatment zone once a day at regular intervals.

[0164] A continuous high-frequency monitoring window of 48 hours was set. To ensure the dynamic correspondence of the data, the timing start point for Comparative Example 2 was set to the instant when the liquid carbon source was added on the same day.

[0165] Using a sealed sampler designed to prevent oxygen contamination, water samples were collected every 4 hours at a depth of 0.5 meters in the middle of the anoxic treatment zone of the two controlled-flow attachment treatment systems.

[0166] After the water sample was filtered through a 0.45 μm filter membrane, the concentration of residual total organic carbon in the water was determined using a total organic carbon analyzer, and the concentration of volatile fatty acids that can be directly utilized by denitrifying bacteria was quantitatively analyzed using a gas chromatograph.

[0167] By combining the total amount of nitrogen removal and the total amount of carbon source consumption within the 48-hour monitoring period, the unit nitrogen removal carbon consumption ratio of the two systems is calculated to evaluate the actual engineering utilization rate of the carbon source.

[0168] Table 4. Test data on carbon source release kinetics and utilization rate in the anoxic treatment zone.

[0169]

[0170] The "-" indicates that the item has no corresponding value or is not applicable.

[0171] See appendix Figure 4 , attached Figure 4 The study demonstrated the low concentration distribution characteristics of the carbon source, which remained stable during a 48-hour continuous monitoring period, by using the total organic carbon envelope and volatile fatty acid scattering.

[0172] See appendix Figure 5 , attached Figure 5 The study uses total organic carbon envelope and volatile fatty acid scatter plots (diamond markers) to demonstrate the dynamic process of rapid erosion and decay of carbon source concentration in water over time after a single addition of liquid carbon source in Comparative Example 2.

[0173] Based on the measured data recorded in Table 4 and the attached... Figure 4 and attached Figure 5 Information analysis showed that conventional liquid carbon source addition methods caused significant substrate concentration fluctuations in flowing receiving water bodies.

[0174] Taking Comparative Example 2 as an example, in the initial stage after dosing, the total organic carbon concentration in the anoxic treatment zone rapidly increased to 118.6 mg / L. In actual river or lake restoration projects, instantaneous high concentrations often exceed the metabolic limits of local denitrifying microorganisms. Because the receiving water body is constantly flowing and changing, a large amount of dissolved carbon sources that cannot be captured by the attached bacteria in time will diffuse and be lost downstream with the water flow.

[0175] As time progressed, by the 12th hour of monitoring, the concentration of directly usable volatile fatty acids in the water had decreased to 2.1 mg / L, which was insufficient to support a normal denitrification rate. This imbalance, characterized by an excess of substrate in the early stages and a shortage of supply in the later stages, resulted in a carbon consumption ratio of 14.2 per unit of nitrogen removal in Comparative Example 2, highlighting the engineering limitations of single-use reagent addition in open water where ineffective losses occur.

[0176] Unlike the pulsed decay process observed in Comparative Example 2, Example 1 exhibited high interfacial release stability during the 48-hour test period. The concentrations of total organic carbon and volatile fatty acids in the water did not show a surge in peak values, but rather fluctuated steadily within low concentration ranges of 16.5–22.3 mg / L and 8.4–12.7 mg / L, respectively.

[0177] Combining the degradation characteristics of the solid-phase carrier, the dual-effect polymer carrier continuously sheds small-molecule carbon sources into the surrounding microenvironment through hydrolysis. These organic substances are rapidly consumed by denitrifying microorganisms tightly attached to the nonwoven fabric strips within the brief physical space of outward diffusion. This in-situ, fixed-point slow-release mechanism weakens the interference of water flow scouring effect on substrate concentration, reducing the unit denitrification carbon consumption ratio in Example 1 to 4.8, and stabilizing the actual utilization rate of carbon sources within a reasonable range that balances economy and treatment efficiency.

Claims

1. A nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents, characterized in that, Includes the following steps: A flow-controlled attachment treatment system is constructed in the receiving water body, consisting of a pretreatment zone, an aerobic deflector zone, an ecological buffer dam (5), and an anoxic treatment zone in sequence; Spray the combined bacterial agent working solution to allow microorganisms to colonize and form a film on the non-woven fabric strips in the anoxic treatment area; The aerobic baffle zone is aerated and oxygenated, and microorganisms degrade organic matter and oxidize ammonia nitrogen into nitrate nitrogen. As the water flows through the ecological buffer dam (5), the alkalinity released in situ neutralizes the acidic substances, thus controlling the pH of the water flow. Water flows into the anoxic treatment zone, which is in a low dissolved oxygen state. The anoxic treatment zone is equipped with a permeable mesh bag (7) containing a dual-effect polymer carrier. The dual-effect polymer carrier hydrolyzes and releases volatile fatty acids. The denitrifying bacteria use the volatile fatty acids to reduce nitrate nitrogen to nitrogen gas to achieve denitrification. Meanwhile, the dual-effect polymer carrier releases magnesium ions, which react with phosphate ions in the water to form precipitates that are trapped in the micropores of the dual-effect polymer carrier. After continuous operation, the permeable mesh bag (7) and the dual-effect polymer carrier adsorbed with solid phosphorus are recovered and replaced, the non-woven fabric strips are rinsed, phosphorus removal is completed and the next treatment cycle begins.

2. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 1, characterized in that, The specific structure of the flow control attachment processing system is as follows: The preprocessing area is equipped with an interception net (1); The aerobic baffle zone has a flexible flow guide wall (2) that hangs down from the bottom in an alternating manner to form a baffle channel. A microporous aeration disc (3) is arranged at the bottom and connected to a dissolved oxygen sensor (4). The ecological buffer dam (5) is enclosed by a metal gabion and filled with oyster shells and limestone. The hypoxia treatment area is provided with a liftable support (6) made of nylon mesh, and multiple non-woven fabric strips are tied to the liftable support (6). The water-permeable mesh bag (7) is set in the lower middle part of the liftable support (6) through the non-woven fabric strips.

3. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 1, characterized in that, The concentration of the combined bacterial agent working solution applied by spraying is 30 mg / L to 50 mg / L, and the application is carried out continuously for 3 to 5 days. The dissolved oxygen in the aerobic baffle zone is kept stable at 6.0 mg / L to 8.0 mg / L, and the hydraulic retention time is controlled at 4 to 6 hours. The pH of the effluent from the ecological buffer dam (5) is maintained at 7.0 to 7.5; The dissolved oxygen level in the anoxic treatment zone was below 0.5 mg / L; The continuous operation cycle is 30 to 45 days.

4. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 1, characterized in that, The dual-effect polymer carrier is made from raw materials comprising the following parts by weight: 40-45 parts corn starch; 30-35 parts of polycaprolactone; 10-12 parts of polyvinyl alcohol; 8-12 parts of lightly calcined magnesium powder; 3-5 parts sodium alginate; Sodium bicarbonate 1-2 parts.

5. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 4, characterized in that, The preparation method of the dual-effect polymeric carrier includes: The polycaprolactone was heated to 80°C to 90°C until completely melted, and the polyvinyl alcohol, corn starch and lightly calcined magnesium powder were added in sequence. The mixture was then stirred at a constant temperature of 500 rpm to 800 rpm for 20 to 30 minutes to obtain a paste-like blend. When the temperature is lowered to 50℃~60℃, sodium alginate and sodium bicarbonate are added, and the mixture is stirred continuously for 15~20 minutes to prepare the mixture. The mixture is extruded into strips with a diameter of 5 mm to 10 mm using a screw extruder and then granulated. The granules are then immersed in a calcium chloride solution with a mass fraction of 2% to 4% for ion-crosslinking and curing for 12 to 24 hours. Remove and rinse, then dry at 40℃~50℃ for 24~36 hours to obtain the dual-effect polymer carrier.

6. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 1, characterized in that, The combined microbial agent working solution is made from raw materials containing the following proportions: A solid fermentation substrate and autotrophic nitrifying bacteria liquid with a mass ratio of (80-90):(10-20); Brown sugar is added at a rate of 1.2 wt% to 1.8 wt% of the total mass of the mixture of the solid fermentation substrate and the autotrophic nitrifying bacteria solution. The amount of water added is 7.3 to 11.5 times the total mass of the mixture of the solid fermentation substrate and the autotrophic nitrifying bacteria liquid.

7. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 6, characterized in that, The preparation method of the solid fermentation substrate includes: Take 70wt% to 80wt% of chicken manure dry matter and mix it with 20wt% to 30wt% of rice husk powder as the fermentation substrate; Add the first fermentation powder at 1wt% to 3wt% of the total mass of the fermentation substrate, adjust the moisture content to 55% to 60%, and aerobic ferment at 60℃ to 65℃ for 2 to 3 days. Add 5 wt% to 8 wt% of the initial dry weight of the fermentation substrate to the second fermentation powder dissolved in warm water, adjust the moisture content to 70% to 75%, and continue fermentation at 65℃ to 70℃ for 5 to 8 days. Then cool and dry to obtain the solid fermentation substrate.

8. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 7, characterized in that, The first baking powder contains Bacillus subtilis, Saccharomyces cerevisiae, and Streptomyces actinomycetes; The second baking powder contains thermophilic Bifidobacterium, compost bacillus, and River tafen.

9. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 6, characterized in that, The method for preparing the autotrophic nitrifying bacteria solution includes: Using inorganic ammonium salt as the sole nitrogen source, and under conditions of pH 7.5–8.0 and temperature 28℃–32℃, Nitrosomonas and Nitrifying Bacillus were independently cultured to prepare the autotrophic nitrifying bacteria solution.

10. The nitrogen and phosphorus removal treatment process for receiving water bodies based on combined nitrifying microbial agents according to claim 9, characterized in that, The preparation method of the combined bacterial agent working solution includes: Take the solid fermentation substrate and the autotrophic nitrifying bacteria liquid and mix them at room temperature; Add the brown sugar and water, and let stand at 20℃~25℃ for 1.5~2.5 hours to activate, so as to obtain the combined bacterial agent working solution with a mass fraction of 8%~12%.

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