A high-efficiency denitrification suspended filler for river management and its preparation method

Abstract

This invention discloses a high-efficiency denitrification suspended packing material for river treatment and its preparation method, belonging to the field of water treatment technology. The preparation method includes the following steps: mixing sludge-based biochar with PHBV to prepare a composite biochar mixed packing material; loading the composite biochar mixed packing material onto the surface of a polyurethane sponge to form a modified polyurethane sponge; placing the modified polyurethane sponge in a reactor for reaction, finally obtaining a denitrification suspended packing material with an internally attached biofilm. Ultrasonic bonding of biochar and PHBV improves their water solubility, reactivity, adsorption performance, and biological activity, enabling the modified packing material to interact more efficiently with target pollutants and enhancing its purification capacity.

Description

[Technical Field]

[0001] This invention belongs to the field of water treatment technology, specifically relating to a high-efficiency denitrification suspended packing material used for river management. [Background Technology]

[0002] With the acceleration of urbanization and the expansion of industrial development, river water environment problems are becoming increasingly serious. Pollution in rivers leads to issues such as hypoxia and eutrophication, severely impacting the health of aquatic ecosystems and the sustainable development of cities. Eutrophication is a water pollution phenomenon caused by the excessive discharge of nutrients such as nitrogen and phosphorus into water bodies, and it is a common water quality problem worldwide. Eutrophication is mainly caused by the discharge of exogenous nutrients, with nitrogen being one of the main contributing factors. Therefore, controlling nitrogen-containing pollutants is crucial for the remediation of eutrophication.

[0003] Currently, biofilm technology is the most widely used river water treatment process. However, in actual river water treatment, biofilm technology suffers from drawbacks such as slow biofilm formation, low biofilm quantity, and low nitrogen removal efficiency, as exemplified by the continuous flow fluidized bed biofilm composite reactor and deep ammonia and phosphorus removal method for wastewater developed by Qingdao Water Group Co., Ltd. (patent application number 202411076856). Therefore, a biofilm packing material is needed to achieve rapid biofilm formation and efficient nitrogen removal in river water treatment systems.

[0004] In existing technologies, traditional porous inorganic fillers such as activated carbon, diatomaceous earth, ceramsite, and zeolite, while widely used, suffer from excessive density that can cause airflow resistance and affect stable equipment operation. Traditional organic materials such as corn cob powder and bamboo powder, while providing carriers and carbon sources, release carbon sources too quickly, leading to a lack of carbon sources for later denitrification and thus reducing denitrification efficiency. For example, the corn cob filler used in a high-efficiency nitrogen and phosphorus removal filler for aquaculture wastewater developed by Guangdong Liankun Group Co., Ltd. (patent application number 202410696354.8). Organic polymer fillers such as polyvinyl chloride and polyurethane sponge suspension fillers, although low in density, have smooth, hydrophobic surfaces, resulting in slow biofilm formation in the reactor and affecting purification efficiency, thus limiting their application in river water denitrification. For example, the preparation method of an iron-manganese composite-based porous polyurethane cement sponge filler developed by Dongguan University of Technology uses polyurethane sponge cement filler (patent application number 202410853176.5). The synergistic application of organic biodegradable polymer slow-release carbon source fillers with inorganic materials has not been widely utilized. [Summary of the Invention]

[0005] To address the shortcomings of existing technologies, the technical problem to be solved by this invention is to provide a highly efficient denitrification suspended filler for river management and its preparation method, thereby solving the problems of slow biofilm formation and low microbial denitrification activity of existing carriers.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] First, a method for preparing a highly efficient denitrification suspended filler for river management is provided, comprising the following steps:

[0008] Composite biochar mixed packing material is prepared by mixing sludge-based biochar with PHBV;

[0009] A modified polyurethane sponge is formed by loading a composite biochar filler onto the surface of a polyurethane sponge.

[0010] Modified polyurethane sponge was placed in a bioreactor for reaction, and finally a denitrification suspension packing material with an internally attached biofilm was obtained.

[0011] Preferably, the preparation method of the sludge-based biochar is as follows: First, the residual sludge after the sewage treatment plant has treated domestic wastewater is naturally air-dried or heated and dried; then, it is mechanically crushed and sieved to obtain the sludge raw material for sludge-based biochar; then, the raw materials of sludge-based biochar, including sludge, diatomaceous earth, iron powder and starch, are mechanically mixed and pyrolyzed at high temperature, cooled and then ground and sieved to obtain sludge-based biochar.

[0012] Preferably, the mass ratio of each raw material in the sludge-based biochar is: 65%-75% sludge, 13%-20% diatomaceous earth, 7%-10% iron powder and 5%-8.5% starch.

[0013] Preferably, the high-temperature pyrolysis process is as follows: pyrolysis in a muffle furnace at 450-600℃ for 30-50 minutes; and / or, after cooling, grinding and sieving to obtain sludge-based biochar.

[0014] Preferably, the preparation method of the composite biochar mixed packing is as follows: sludge-based biochar and PHBV are mixed according to a set mass ratio, and deionized water is added and stirred evenly; then it is placed in an ultrasonic cleaner for ultrasonic treatment; after ultrasonic treatment, it is placed for cooling; finally, it is left to stand for a set time to obtain the composite biochar mixed packing.

[0015] Preferably, the mass ratio of the sludge-based biochar to PHBV is 2-8:1; and / or, the mixture is ultrasonicated in an ultrasonic cleaner for 1-3 hours with an ultrasonic power of 250-350W; and / or, it is left to stand for 10-14 hours to obtain the composite biochar mixed packing.

[0016] Preferably, the modification method of the polyurethane sponge is as follows: the composite biochar mixed filler is loaded onto the surface of the polyurethane sponge using an adhesive.

[0017] Preferably, the adhesive is prepared by mixing 1.5-2.5% sodium alginate aqueous solution and 1.5-2.8% polyvinyl alcohol aqueous solution.

[0018] Preferably, the modified polyurethane sponge is enriched, acclimatized, and coated with biofilm in a bioreactor for 11-20 days, and then finally removed to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0019] In addition, the present invention also provides a high-efficiency denitrification suspended filler for use in river management, which is prepared by the aforementioned high-efficiency denitrification suspended filler preparation method.

[0020] The present invention, by adopting the above technical solution, has the following beneficial effects:

[0021] The suspended filler of the present invention can be used for the removal of nitrogen-containing pollutants in rivers. The components of the high-efficiency denitrification suspended filler of the present invention used for river management include: a composite biochar mixed filler made by mixing sludge-based biochar and PHBV, and a polyurethane sponge. The composite biochar mixed filler is adhered to the polyurethane sponge by an adhesive.

[0022] The PHBV (3-hydroxybutyric acid-co-3-hydroxyvalerate) in the packing material can be hydrolyzed into soluble small molecules under the action of extracellular enzymes of microorganisms. These substances serve as carbon sources and electron donors for microorganisms and participate in the denitrification process, thereby promoting water purification effects such as nitrogen removal.

[0023] Sludge-based biochar can immobilize microorganisms on activated carbon, increasing the adsorption capacity and lifespan of activated carbon, and enhancing its ability to degrade organic matter in water. The added iron powder has excellent nitrogen adsorption properties, effectively removing nitrogen from river water and increasing the activity of microorganisms in the biofilm. The sludge-based biochar and iron powder work together to enhance the indirect nitrogen removal function of iron. This invention uses ultrasound to combine the composite biochar mixed packing material with PHBV, thereby improving its water solubility, reactivity, adsorption performance, and biological activity. This rapidly increases the amount of microbial biofilm, allowing the modified packing material to interact more efficiently with target pollutants and enhancing its purification capacity.

[0024] By using polyurethane sponge with a large specific surface area as a carrier, a suitable environment for microbial growth is provided, which is conducive to the rapid formation of biofilm.

[0025] The packing material of this invention provides a suitable microenvironment, which is conducive to the enrichment of denitrification-related microorganisms (such as nitrifying bacteria). The porous structure and hydrophilic surface of the packing material provide good attachment points for microorganisms, promote the formation of biofilm, and enable it to exhibit higher purification efficiency when treating river water.

[0026] By using a surface-loaded composite biochar mixed packing material, the packing material facilitates rapid biofilm formation, and the PHBV it carries has the function of promoting the activity of microbial denitrification-related enzymes, thereby improving the denitrification effect.

[0027] This invention allows for flexible adjustment of the composite biochar mixed packing material and PHBV ratio according to different water quality conditions, enabling efficient denitrification in rivers with varying pollution levels.

[0028] In this invention, the packing material does not degrade or become toxic to microorganisms when immersed in wastewater for extended periods. Compared to other materials such as polyvinyl chloride, this packing material exhibits superior chemical resistance and biocompatibility, maintaining stable performance in complex environments and ensuring its long-term effectiveness.

[0029] The packing material of this invention provides a good growth environment for microorganisms. Microorganisms exhibit high activity on this packing material and can rapidly degrade organic matter and other pollutants in wastewater, further improving the water purification effect.

[0030] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. [Attached Image Description]

[0031] The invention will be further described below with reference to the accompanying drawings:

[0032] Figure 1 This is a flowchart illustrating the preparation process of the iron-manganese composite porous polyurethane cement sponge filler of the present invention.

[0033] Figure 2 The images are SEM images of the surface morphology of the high-efficiency denitrification suspended packing prepared in Examples 1-4 of the present invention before river treatment, wherein (a) to (d) are SEM images of the biofilm formed on the surface of the polyurethane sponge in Examples 1-4, respectively.

[0034] Figure 3 These are microscopic images of the surface of the polyurethane sponge packing prepared in Examples 1-4 of the present invention after being applied to river management. Among them, (a) to (d) are microscopic images of the surface of the polyurethane sponge packing in Examples 1-4, respectively.

[0035] Figure 4 This is a sample image of the high-efficiency denitrification suspension packing prepared in Example 1 of the present invention;

[0036] Figure 5 The images show the finished products of the high-efficiency denitrification suspended filler prepared in Examples 1-4 of this invention after being applied to river management. In particular, (a) to (d) are finished products of the high-efficiency denitrification suspended filler prepared in Examples 1-4 after being applied to river management.

[0037] Figure 6Gram staining images of the high-efficiency denitrification suspension packing prepared in Examples 1-4 of the present invention after application to river management, wherein (a) to (d) are Gram staining images of the high-efficiency denitrification suspension packing prepared in Examples 1-4 after application to river management;

[0038] Figure 7 This is a diagram showing the carbon release of the high-efficiency denitrification suspension packing prepared in Example 2 of the present invention;

[0039] Figure 8 The images show ammonia nitrogen data of the high-efficiency denitrification suspended packing prepared in Examples 1-4 of this invention after being applied to river treatment. In the images, (a) to (d) are ammonia nitrogen data of the high-efficiency denitrification suspended packing prepared in Examples 1-4 after being applied to river treatment.

[0040] Figure 9 The graphs show the total nitrogen data of the high-efficiency denitrification suspended filler prepared in Examples 1-4 of this invention after being applied to river management. In the graphs, (a) to (d) are the total nitrogen data of the high-efficiency denitrification suspended filler in Examples 1-4 after being applied to river management.

Detailed Implementation Methods

[0041] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0042] Those skilled in the art will understand that, without conflict, the features in the following embodiments and implementations can be combined with each other.

[0043] This invention provides a high-efficiency denitrification suspended filler for use in river management and its preparation method, the preparation method comprising the following steps:

[0044] Composite biochar mixed packing material is prepared by mixing sludge-based biochar with PHBV;

[0045] A modified polyurethane sponge is formed by loading a composite biochar filler onto the surface of a polyurethane sponge.

[0046] Modified polyurethane sponge was placed in a bioreactor for reaction, and finally a denitrification suspension packing material with an internally attached biofilm was obtained.

[0047] Preferably, the preparation method of the sludge-based biochar is as follows: First, the residual sludge after the sewage treatment plant has treated domestic wastewater is naturally air-dried or heated and dried; then, it is mechanically crushed and sieved to obtain the sludge raw material for sludge-based biochar; then, the raw materials of sludge-based biochar, including sludge, diatomaceous earth, iron powder and starch, are mechanically mixed and pyrolyzed at high temperature, cooled and then ground and sieved to obtain sludge-based biochar.

[0048] A high-efficiency denitrification suspended filler for use in river management was prepared using the aforementioned method.

[0049] This invention utilizes polyurethane sponge with a large specific surface area as a carrier to provide a suitable environment for microbial growth, facilitating rapid biofilm formation. The sludge-based biochar immobilizes microorganisms on activated carbon, increasing its adsorption capacity, extending its lifespan, and enhancing its ability to degrade organic matter in water. PHBV (3-hydroxybutyric acid-co-3-hydroxyvalerate) in the packing material can be hydrolyzed into soluble small molecules by extracellular enzymes of microorganisms. These substances act as carbon sources and electron donors for microorganisms in the denitrification process, providing sufficient carbon for the biofilm in oligotrophic river water, creating conditions for rapid microbial growth, and thus promoting denitrification and other water purification effects. This truly achieves the synergistic effect of organic biodegradable polymers and inorganic substances. Furthermore, the added iron powder has excellent nitrogen adsorption properties, effectively removing nitrogen from river water and increasing the activity of microorganisms in the biofilm. The combined effect of the sludge-based biochar and iron powder enhances the indirect denitrification function of iron.

[0050] The specific technical solution of this invention is as follows:

[0051] A method for preparing a high-efficiency denitrification suspended filler for river management, comprising the following steps:

[0052] Step 1: Preparation of sludge-based biochar

[0053] First, the residual sludge from the wastewater treatment plant is naturally air-dried. The dried sludge is then mechanically crushed and passed through a 100-150 mesh sieve for later use.

[0054] The proportions of raw materials for sludge-based biochar are as follows: 65%-75% sludge, 13%-20% diatomaceous earth, 7.5%-10% iron powder and 5%-8.5% starch. After mechanical mixing, the raw materials are pyrolyzed in a muffle furnace at a high temperature of 450-600℃ for 30-50 minutes. After cooling, they are then ground through a 100-mesh sieve to obtain sludge-based biochar.

[0055] Step 2: Preparation of composite biochar mixed packing material

[0056] Add a certain amount of sludge-based biochar and PHBV (mass ratio of 3:1) obtained in step 1 to an appropriate amount of deionized water and stir evenly. Place the mixture in an ultrasonic cleaner and sonicate for 1-3 hours at an ultrasonic power of 250-350W. After sonication, allow it to cool and set aside for later use. Let it stand for 10-14 hours to obtain the composite biochar mixed packing.

[0057] Step 3: Modification of polyurethane foam

[0058] The composite biochar mixed filler obtained in step 2 was loaded onto the surface of polyurethane sponge using 1.5-2.5% sodium alginate aqueous solution and 1.5-2.8% polyvinyl alcohol aqueous solution as binders. The loading was successful when the sponge surface was uniformly covered with particles and they were not washed away by water. The modification of polyurethane sponge was then completed.

[0059] Step 4: Formation of biofilm

[0060] The modified polyurethane sponge obtained in step 3 was placed in a reactor, which was a laboratory reactor that was operating stably. After 11-20 days of enrichment, acclimatization, and biofilm formation, it was finally removed to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0061] A high-efficiency denitrification suspended filler was prepared using the aforementioned method for preparing the high-efficiency denitrification suspended filler for use in river management. The suspended filler of the present invention can be used to remove nitrogen-containing pollutants in rivers. The PHBV (3-hydroxybutyric acid-co-3-hydroxyvalerate) in the filler can be hydrolyzed into soluble small molecules under the action of extracellular enzymes of microorganisms. These substances participate in the denitrification process as carbon sources and electron donors for microorganisms, thereby promoting denitrification and other water purification effects.

[0062] This invention utilizes ultrasound to synthesize a composite biochar mix with PHBV, thereby improving its water solubility, reactivity, adsorption performance, and bioactivity. This rapidly increases the biofilm formation, enabling the modified packing to interact more efficiently with target pollutants and enhancing its purification capacity. The packing provides a suitable microenvironment conducive to the accumulation of denitrification-related microorganisms (such as nitrifying bacteria). The porous structure and hydrophilic surface of the packing provide excellent attachment sites for microorganisms, promoting biofilm formation and resulting in higher purification efficiency when treating river water.

[0063] By using a surface-loaded composite biochar mixed packing material, the packing material facilitates rapid biofilm formation, and the PHBV it carries has the function of promoting the activity of microbial denitrification-related enzymes, thereby improving the denitrification effect. This invention allows for flexible adjustment of the composite biochar mixed packing material and the PHBV ratio according to different water quality conditions, enabling efficient denitrification in rivers with different pollution levels.

[0064] In this invention, the packing material does not degrade or become toxic to microorganisms when immersed in wastewater for extended periods. Compared to other materials such as polyvinyl chloride, this packing material exhibits superior chemical resistance and biocompatibility, maintaining stable performance in complex environments and ensuring its long-term effectiveness.

[0065] The packing material of this invention provides a good growth environment for microorganisms. Microorganisms exhibit high activity on this packing material and can rapidly degrade organic matter and other pollutants in wastewater, further improving the water purification effect.

[0066] Example 1:

[0067] 1) The residual sludge from a wastewater treatment plant in Hangzhou, Zhejiang Province, was naturally air-dried. The dried sludge was then mechanically crushed and passed through a 100-mesh sieve for later use. The raw materials for the sludge-based biochar were formulated as follows: 65% sludge, 20% diatomaceous earth, 10% iron powder, and 5% starch. After mechanical mixing, the raw materials were pyrolyzed in a muffle furnace at 550°C for 45 minutes. After cooling, the mixture was then ground through a 100-mesh sieve to obtain the sludge-based biochar.

[0068] 2) Add a certain amount of sludge-based biochar and PHBV (mass ratio of 3:1) obtained in step 1 to an appropriate amount of deionized water and stir evenly. Place it in an ultrasonic cleaner and sonicate for 2 hours at an ultrasonic power of 300W. After sonication, let it cool and set aside for later use. Let it stand for 10 hours to obtain composite biochar mixed packing.

[0069] 3) The composite biochar mixed filler obtained in step 2 is loaded onto the surface of polyurethane sponge using 1.5% sodium alginate aqueous solution and 2% polyvinyl alcohol aqueous solution as binders. The loading is successful when the sponge surface is uniformly covered with particles and they are not washed away by water. The modification of polyurethane sponge is then completed.

[0070] 4) The modified polyurethane sponge obtained in step 3 is placed in a reactor that is a laboratory reactor that is operating stably. After 15 days of enrichment, acclimatization and biofilm formation, it is finally taken out to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0071] Example 2:

[0072] 1) The residual sludge from a wastewater treatment plant in Haining, Zhejiang Province, was naturally air-dried after treating domestic sewage. The dried sludge was then mechanically crushed and passed through a 100-mesh sieve for later use. The raw materials for the sludge-based biochar were formulated as follows: 65% sludge, 20% diatomaceous earth, 10% iron powder, and 5% starch. After mechanical mixing, the raw materials were pyrolyzed in a muffle furnace at 550°C for 45 minutes. After cooling, the mixture was then ground through a 100-mesh sieve to obtain the sludge-based biochar.

[0073] 2) Add a certain amount of sludge-based biochar and PHBV (mass ratio of 3:1) obtained in step 1 to an appropriate amount of deionized water and stir evenly. Place it in an ultrasonic cleaner and sonicate for 2 hours with an ultrasonic power of 310W. After sonication, let it cool and set aside for later use. Let it stand for 12 hours to obtain composite biochar mixed packing.

[0074] 3) The composite biochar mixed filler obtained in step 2 is loaded onto the surface of polyurethane sponge using 1.9% sodium alginate aqueous solution and 2.2% polyvinyl alcohol aqueous solution as binders. The loading is successful when the sponge surface is uniformly covered with particles and they are not washed away by water. The modification of polyurethane sponge is then completed.

[0075] 4) The modified polyurethane sponge obtained in step 3 is placed in a reactor that is a laboratory reactor that is operating stably. After 14 days of enrichment, acclimatization and biofilm formation, it is finally taken out to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0076] Example 3:

[0077] 1) The residual sludge from the treatment of domestic sewage at a wastewater treatment plant in Hangzhou, Zhejiang Province, was naturally air-dried. The dried sludge was then mechanically crushed and passed through a 100-mesh sieve for later use. The raw materials for the sludge-based biochar were formulated as follows: 65% sludge, 20% diatomaceous earth, 10% iron powder, and 5% starch. After mechanical mixing, the raw materials were pyrolyzed in a muffle furnace at 550°C for 50 minutes. After cooling, the mixture was then ground through a 100-mesh sieve to obtain the sludge-based biochar.

[0078] 2) Add a certain amount of sludge-based biochar and PHBV (mass ratio of 3:1) obtained in step 1 to an appropriate amount of deionized water and stir evenly. Place it in an ultrasonic cleaner and sonicate for 1.5 hours with an ultrasonic power of 300W. After sonication, let it cool and set aside for later use. Let it stand for 13 hours to obtain the composite biochar mixed packing.

[0079] 3) The composite biochar mixed filler obtained in step 2 is loaded onto the surface of polyurethane sponge using 2% sodium alginate aqueous solution and 1.7% polyvinyl alcohol aqueous solution as binders. The loading is successful when the sponge surface is uniformly covered with particles and they are not washed away by water. The modification of polyurethane sponge is then completed.

[0080] 4) The modified polyurethane sponge obtained in step 3 is placed in a reactor that is a laboratory reactor that is operating stably. After 13 days of enrichment, acclimatization and biofilm formation, it is finally taken out to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0081] Experiment Example 4

[0082] 1) The residual sludge from a wastewater treatment plant in Haining, Zhejiang Province, was naturally air-dried after treating domestic sewage. The dried sludge was then mechanically crushed and passed through a 100-mesh sieve for later use. The raw materials for the sludge-based biochar were formulated as follows: 65% sludge, 20% diatomaceous earth, 10% iron powder, and 5% starch. After mechanical mixing, the raw materials were pyrolyzed in a muffle furnace at 550°C for 45 minutes. After cooling, the mixture was then ground through a 100-mesh sieve to obtain the sludge-based biochar.

[0083] 2) Add a certain amount of sludge-based biochar and PHBV (mass ratio of 3:1) obtained in step 1 to an appropriate amount of deionized water and stir evenly. Place it in an ultrasonic cleaner and sonicate for 2 hours with an ultrasonic power of 310W. After sonication, let it cool and set aside for later use. Let it stand for 12 hours to obtain composite biochar mixed packing.

[0084] 3) The composite biochar mixed filler obtained in step 2 is loaded onto the surface of polyurethane sponge using 1.9% sodium alginate aqueous solution and 2.2% polyvinyl alcohol aqueous solution as binders. The loading is successful when the sponge surface is uniformly covered with particles and they are not washed away by water. The modification of polyurethane sponge is then completed.

[0085] 4) The modified polyurethane sponge obtained in step 3 is placed in a reactor that is a laboratory reactor that is operating stably. After 14 days of enrichment, acclimatization and biofilm formation, it is finally taken out to obtain a highly efficient denitrification suspended packing material for river management with a large amount of biofilm attached inside.

[0086] Application Example 1

[0087] The morphological changes of the biofilm on the surface of the polyurethane sponge prepared in Example 1 for river management and the denitrification data were investigated after river management.

[0088] A parallel laboratory-scale stainless steel biofilm reactor was established, with an effective volume of 2.2 m³. 3 The reactor was filled with the high-efficiency denitrification suspension packing material prepared in Example 1. The reactor was operated for 30 days, during which the dissolved oxygen concentration was maintained at 7–9 mg / L. The reactor temperature was adjusted to 25 ± 0.5℃, and the reactor water was river water with a total nitrogen concentration of 8 mg / L and a total phosphorus concentration of 3 mg / L.

[0089] Application Example 2

[0090] The morphological changes of the biofilm on the surface of the polyurethane sponge prepared in Example 2 for river management and the denitrification data were investigated after river management.

[0091] A parallel laboratory-scale stainless steel biofilm reactor was established, with an effective volume of 2 m³. 3The reactor was filled with the high-efficiency denitrification suspension packing prepared in Example 2. The reactor was operated for 30 days, during which the dissolved oxygen concentration was maintained at 7–9 mg / L. The reactor temperature was adjusted to 32 ± 0.5℃, and the reactor water was river water with a total nitrogen concentration of 7 mg / L and a total phosphorus concentration of 2.5 mg / L.

[0092] Application Example 3

[0093] The morphological changes of the biofilm on the surface of the polyurethane sponge prepared in Example 3 for river management and the denitrification data were examined after river management.

[0094] A parallel laboratory-scale stainless steel biofilm reactor was established, with an effective volume of 2 m³. 3 The reactor was filled with the high-efficiency denitrification suspension packing prepared in Example 3. The reactor was operated for 30 days, during which the dissolved oxygen concentration was maintained at 7–9 mg / L. The reactor temperature was adjusted to 28 ± 0.5℃, and the reactor water was river water with a total nitrogen concentration of 5 mg / L and a total phosphorus concentration of 5 mg / L.

[0095] Application Example 4

[0096] The morphological changes of the biofilm on the surface of the polyurethane sponge prepared in Example 4 for river management and the denitrification data were examined after river management.

[0097] A parallel laboratory-scale stainless steel biofilm reactor was established, with an effective volume of 2 m³. 3 The reactor was filled with the high-efficiency denitrification suspension packing prepared in Example 4. The reactor was operated for 30 days, during which the dissolved oxygen concentration was maintained at 7–9 mg / L. The reactor temperature was adjusted to 26 ± 0.5℃, and the reactor water was river water with a total nitrogen concentration of 10 mg / L and a total phosphorus concentration of 2.2 mg / L.

[0098] After adding the high-efficiency denitrification suspended packing material used for river management, the denitrification efficiency was significantly improved during river management; the denitrification efficiency of the prepared high-efficiency denitrification suspended packing material for river management increased with the increase of operating time. Although the addition of ordinary polyurethane sponge packing material also had a certain effect on enhancing the denitrification reaction, the difference was significant compared with the modified high-efficiency denitrification suspended packing material for river management.

[0099] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Those skilled in the art should understand that the invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.

Claims

1. A method for preparing a high-efficiency denitrification suspended filler for riverway management, characterized in that, It comprises the following steps: The composite biochar mixed filler is prepared by mixing the sludge-based biochar and PHBV; The modified polyurethane sponge is formed by loading the composite biochar mixed filler on the surface of the polyurethane sponge; The modified polyurethane sponge is placed in a bioreactor for reaction, and finally the denitrification suspended filler with internal attached biofilm is obtained. The preparation method of the sludge-based biochar comprises the following steps: firstly, the residual sludge after the treatment of domestic wastewater in a sewage plant is naturally air-dried or heated and dried; then, mechanical crushing and sieving are performed to obtain sludge raw materials of the sludge-based biochar; then, the sludge-based biochar raw materials, including sludge, diatomite, iron powder and starch, are mechanically mixed and pyrolyzed at high temperature, and after cooling, the sludge-based biochar is obtained by grinding and sieving, wherein the mass ratio of the sludge-based biochar raw materials is 65%-75% of sludge, 13%-20% of diatomite, 7%-10% of iron powder and 5%-8.5% of starch; and the modification method of the polyurethane sponge comprises the following steps: the composite biochar mixed filler is loaded on the surface of the polyurethane sponge by using an adhesive.

2. The method of claim 1, wherein the high-efficiency denitrification suspended filler is prepared by the steps of: The pyrolysis process at high temperature comprises the following steps: the muffle furnace is pyrolyzed at high temperature of 450-600 DEG C for 30-50 min; and / or, after cooling, the sludge-based biochar is obtained by grinding and sieving. ​ 3. The method of claim 1, wherein the high-efficiency denitrification suspended media is prepared by the steps of: The preparation method of the composite biochar mixed filler comprises the following steps: the sludge-based biochar and PHBV are configured according to a set mass ratio, and then deionized water is added and stirred uniformly; then, ultrasonic treatment is performed in an ultrasonic cleaner; after the ultrasonic treatment is completed, the mixture is cooled; finally, the mixture is left to stand for a set time, and the composite biochar mixed filler is obtained. ​ 4. The method of claim 3, wherein the high-efficiency denitrification suspended media is prepared by the steps of: The mass ratio of the sludge-based biochar and PHBV is 2-8:1; and / or, the ultrasonic treatment is performed in the ultrasonic cleaner for 1-3 h, and the ultrasonic power is 250-350 W; and / or, the composite biochar mixed filler is obtained by leaving to stand for 10-14 h. ​ 5. The method of claim 1, wherein the high-efficiency denitrification suspended media is prepared by the steps of: The adhesive is prepared by mixing 1.5-2.5% of sodium alginate aqueous solution and 1.5-2.8% of polyvinyl alcohol aqueous solution. ​ 6. The method for preparing high-efficiency denitrification suspension packing according to claim 1, characterized in that, The modified polyurethane sponge is left to stand in the bioreactor for 11-20 days for enrichment, domestication and biofilm formation, and finally the high-efficiency denitrification suspended filler with a large amount of internal attached biofilm is obtained for river treatment.

7. A high-efficiency denitrification suspended filler for riverway management, characterized in that, The high-efficiency denitrification suspended filler is prepared by using the preparation method in any one of claims 1 to 6.

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