Method for preparing biological filter material based on municipal sludge and traditional Chinese medicine waste residues

Abstract

The invention relates to a method for preparing a biological filter material based on municipal sludge and traditional Chinese medicine waste residues, and belongs to the field of solid waste resource utilization. According to the method, the crude fiber characteristic of the traditional Chinese medicine waste residues is utilized, biochar is prepared through a pyrolysis method, the biochar is mixed with dried, crushed and screened municipal sludge and the like and then sintered, dipping and biofilm culturing treatment are conducted, and finally the biological filter material is obtained. The method has the advantages that the adsorption performance of the filter material is enhanced, harmless, reduction and resource utilization of the municipal sludge and the traditional Chinese medicine waste residues is realized, and the method conforms to the solid waste treatment principle in China and has a wide development prospect.

Description

Technical Field

[0001] The present invention relates to a method for preparing a biological filter material from municipal sludge and Chinese medicine residue, and belongs to the field of solid waste resource utilization. Background Art

[0002] In recent years, the production of urban sewage and sludge in China has shown an increasing trend year by year. In response to this situation, China has issued the Implementation Plan for the Harmless Treatment and Resource Utilization of Sludge, clearly stating that by 2025, the harmless treatment rate of urban sludge nationwide should reach over 90%. Under the framework of the current concept of resource recycling and green and low-carbon development, safely and efficiently treating sludge has become a crucial task. The core principles of sludge treatment and disposal revolve around the resourceization, harmlessness, and reduction of sludge. Currently, the main technologies used in the sludge treatment field include landfilling, incineration, agricultural and forestry utilization, biogas production through digestion, and biochar preparation. However, these methods have their own advantages and disadvantages. Therefore, new methods for sludge resource utilization have been actively explored and tried in recent years, with the aim of achieving more efficient and sustainable progress in the sludge treatment field.

[0003] With the booming rise of the traditional Chinese medicine industry, while creating significant economic benefits, it has also brought new challenges and pressures to Chinese medicine enterprises and the entire society. The core issue focuses on the scientific disposal and resource utilization of Chinese medicine residue. Reasonably and efficiently using Chinese medicine residue can not only significantly reduce resource consumption, improve the recycling rate of the residue, and optimize the ecological environment quality, but also has far-reaching significance for promoting the traditional Chinese medicine industry to enter a virtuous cycle of development. In recent years, the academic and industrial circles have carried out extensive research on the resource utilization of Chinese medicine residue, mainly focusing on fields such as preparing edible mushroom culture media, livestock and poultry feed, and producing organic fertilizers using the residue as a matrix, and a series of positive results have been achieved, showing good application prospects. Based on the high fiber content of Chinese medicine residue, the present invention can make biochar with better adsorption effect and mix it with raw materials such as urban sludge to prepare a better biological filter material.

[0004] At present, the general requirements for filter media in biological filters are as follows: (1) Large specific surface area: Selecting porous inert carriers is beneficial to the adsorption, growth and formation of biofilms by microorganisms. (2) Good mechanical strength: To reduce the breakage rate. (3) Regular spherical fillers: To make the air distribution and water distribution uniform and the water flow resistance small. (4) Having a certain porosity and roughness: It is beneficial to the attachment and growth of microbial films. (5) Filter media with a small relative density is convenient for backwashing: Ceramsite is a relatively good filter media. Currently, in the field of wastewater biological treatment technology in China, the R & D and innovation of a variety of new fillers have been witnessed, which has given rise to the establishment of a series of production enterprises and formed an industrial pattern with rich product varieties and a relatively complete system. However, despite the wide variety of filter media on the market, they each have limitations in terms of physical properties and film attachment ability. Specifically, the surfaces of some filter media are smooth, resulting in difficulty for microorganisms to effectively attach and form biofilms; some are prone to breakage due to insufficient strength; and there are also filter media that are restricted in their wide application due to high prices and difficult regeneration. More critically, the vast majority of currently used filter media lack the ability to promote microbial activity. In view of this, the development of a contact filter media with excellent performance constitutes one of the crucial factors for ensuring the successful application of the biological aerated filter technology in the field of water treatment. Summary of the Invention

[0005] The present invention aims to propose a technical solution for preparing biological filter media based on urban sludge and Chinese medicine residues. This solution utilizes the rich crude fiber components in Chinese medicine residues, mixes them with raw materials such as urban sludge after carbonization treatment, and prepares biological filter media through a pressing and forming process. By combining urban sludge with carbonized Chinese medicine residues, the adsorption performance of the prepared biological filter media is significantly improved. This technical solution not only realizes the harmless treatment of sludge and Chinese medicine residues, but also realizes resource recycling, which conforms to the principles of harmlessness, reduction and resource utilization advocated in the field of solid waste treatment in China. Therefore, this technical solution has significant development potential and application prospects.

[0006] The present invention is realized through the following technical solutions: A method for preparing biological filter media based on urban sludge and Chinese medicine residues, the method comprising: Step 1: Preparing biochar from Chinese medicine residues; Step 2: Mixing urban sludge with the prepared biochar and other raw materials in proportion and pressing them into shape; Step 3: Drying and calcining the shaped filter media, cooling it, and then impregnating and film-forming it with hydrochloric acid by ultrasonic wave.

[0007] Further, for the preparation of biochar from Chinese medicine residues, most of the moisture in the Chinese medicine residues (such as Acanthopanax senticosus, Astragalus membranaceus, Panax notoginseng, etc.) is filtered out, dried to a constant weight and then pulverized, put into a tubular furnace for pyrolysis into carbon, after the pyrolysis is completed, nitrogen is introduced until the inside of the furnace cavity cools to room temperature, and then sieved to obtain biochar.

[0008] Furthermore, the urban sludge and each raw material are mixed in proportion and pressed into shape. It is characterized in that each raw material is urban sludge, clay, binder, and carbonized traditional Chinese medicine residue, and diatomite is used as the binder.

[0009] Preferably, the addition ratio of each raw material is as follows: the biochar prepared from the traditional Chinese medicine residue accounts for 5%-10% of the total mass of the material; the sludge accounts for 15%-60% of the total mass of the material; the clay accounts for 30%-75% of the total mass of the material; the binder accounts for 0.6%-10% of the total mass of the material. An appropriate amount of water is added to the mixed material, and after stirring evenly, it is pressed into a cylindrical shape using a mold.

[0010] Furthermore, the formed filter material is dried and calcined, and after cooling, it is impregnated with hydrochloric acid by ultrasonic wave and then subjected to biofilm formation treatment.

[0011] Preferably, the formed filter material is transferred to an oven for drying. The drying temperature is 100-120°C, and the drying time is 45-60 min. The dried filter material is transferred to a muffle furnace for calcination for 2.5-3 h, and the calcination temperature is 450-550°C to obtain a semi-finished biofilter material. The heat-treated biofilter material is impregnated with 5% hydrochloric acid by ultrasonic wave. The obtained semi-finished biofilter material is immersed in a microbial nutrient solution for 30-45 min, and microbial inoculation is carried out for 5-7 d to form a biofilm on the surface of the filter material, obtaining a biofilm-formed biomass filter material.

[0012] Furthermore, the specific steps for preparing biochar from the traditional Chinese medicine residue are as follows: Most of the moisture in the traditional Chinese medicine residue is filtered out and then dried to a constant weight. The dried residue is crushed to less than 2 mm. The residue is put into a tubular furnace for pyrolysis into carbon. Before the start of pyrolysis, high-purity nitrogen with a flow rate of 100 mL / min is continuously introduced into the tubular furnace for 20 min to exhaust the air in the furnace cavity and form an oxygen-deficient environment. After the start of pyrolysis, the nitrogen flow rate is adjusted to 50 mL / min, and the furnace body is heated from room temperature to the target temperature of 450-700°C at a heating rate of 10°C / min and maintained at the target temperature for 1 h. After the pyrolysis process is completed, nitrogen is continuously introduced until the quartz tube in the furnace cavity cools to room temperature. Subsequently, the biochar is taken out, ground and sieved through 60 meshes, and finally stored in a sealed manner.

[0013] Furthermore, the specific steps for preparing the biofilter material are as follows: Step 1: The urban sludge is dried, crushed, and sieved. The purpose of drying is to remove the moisture in the sludge, and the particle size of the sludge is 20-40 meshes; Step 2: Mixing and shaping Mix the prepared biochar with the treated sludge in a certain proportion. The addition amounts of each raw material are as follows: the biochar prepared from Chinese medicine residues accounts for 5%-10% of the total mass of the material; the sludge accounts for 15%-60% of the total mass of the material; the clay accounts for 30%-75% of the total mass of the material; the binder accounts for 0.6%-10% of the total mass of the material. Add an appropriate amount of water to the mixed materials, stir evenly, and then press them into a cylindrical shape using a mold; Step 3: Drying and heat treatment Transfer the formed filter material into an oven for drying. The drying temperature is 100-120°C, and the drying time is 45-60 min to remove the moisture in the filter material and improve its strength and stability; Transfer the dried filter material into a muffle furnace for calcination for 2.5-3 h. The calcination temperature is 450-550°C. After the calcination is completed, naturally cool it to room temperature to obtain a semi-finished biofilter material; Step 4: Post-treatment and biofilm formation Ultrasonically impregnate the heat-treated biofilter material with 5% hydrochloric acid at a solid-liquid ratio of 1:10 for 30 min, and then repeatedly rinse it with pure water until it is neutral, and dry it to obtain the final sample. This step can further remove the impurities on the surface of the filter material and improve its performance. Soak the obtained semi-finished biofilter material in a microbial nutrient solution for 30-45 min and carry out microbial inoculation for 5-7 d to form a biofilm on the surface of the filter material, and obtain a biofilm-formed biomass filter material. The molar ratio of carbon, nitrogen, and phosphorus in the nutrient solution is generally 100:5:1. Specific embodiments

[0014] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention is further described in detail through the following embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1

[0015] The present invention is realized through the following technical solutions: A method for preparing a biofilter material based on urban sludge and Chinese medicine residues, the method includes: Step 1: Prepare biochar from Chinese medicine residues; Step 2: Mix the urban sludge with the prepared biochar and other raw materials in proportion and press them into shape; Step 3: Dry, calcine the formed filter material, cool it, and ultrasonically impregnate it with hydrochloric acid and form a biofilm.

[0016] Furthermore, for the biochar prepared from Chinese medicine residues, most of the moisture in the Chinese medicine residues (such as Eleutherococcus senticosus, Astragalus membranaceus, Panax notoginseng, etc.) is filtered off, dried to constant weight, pulverized, put into a tubular furnace for pyrolysis into carbon, and after the pyrolysis is completed, nitrogen is introduced until the inside of the furnace cavity cools to room temperature, and then sieved to obtain the biochar.

[0017] Further, the urban sludge and each raw material are mixed in proportion and pressed into shape, characterized in that each raw material is urban sludge, clay, binder, carbonized traditional Chinese medicine residue, and the binder is diatomite as the binder.

[0018] Preferably, the addition ratio of each raw material is: the biochar prepared from the traditional Chinese medicine residue accounts for 5%-10% of the total mass of the material; the sludge accounts for 15%-60% of the total mass of the material; the clay accounts for 30%-75% of the total mass of the material; the binder accounts for 0.6%-10% of the total mass of the material. An appropriate amount of water is added to the mixed material, and after stirring evenly, it is pressed into a cylindrical shape by a mold.

[0019] Further, the formed filter material is dried and calcined, and after cooling, it is ultrasonically impregnated with hydrochloric acid and then subjected to biofilm formation treatment.

[0020] Preferably, the formed filter material is transferred to an oven for drying, the drying temperature is 100-120°C, and the drying time is 45-60 min. The dried filter material is transferred to a muffle furnace for calcination for 2.5-3 h, and the calcination temperature is 450-550°C to obtain a semi-finished biological filter material. The heat-treated biological filter material is ultrasonically impregnated with 5% hydrochloric acid, and the obtained semi-finished biological filter material is immersed in a microbial nutrient solution for 30-45 min and inoculated with microorganisms for 5-7 d to form a biofilm on the surface of the filter material, obtaining a biofilm-coated biomass filter material.

[0021] Further, the specific steps for preparing biochar from the traditional Chinese medicine residue are as follows: Most of the moisture in the traditional Chinese medicine residue is filtered off and dried to a constant weight. The dried residue is crushed to less than 2 mm and put into a tube furnace for pyrolysis into carbon. Before the start of pyrolysis, high-purity nitrogen with a flow rate of 100 mL / min is continuously introduced into the tube furnace for 20 min to exhaust the air in the furnace cavity and form an oxygen-deficient environment. After the start of pyrolysis, the nitrogen flow rate is adjusted to 50 mL / min, and the furnace body is heated from room temperature to the target temperature of 450-700°C at a heating rate of 10°C / min and maintained at the target temperature for 1 h. After the pyrolysis process is completed, nitrogen is continuously introduced until the quartz tube in the furnace cavity cools to room temperature. Subsequently, the biochar is taken out, ground and sieved through 60 meshes, and finally stored in a sealed manner.

[0022] Further, the specific steps for preparing the biological filter material are as follows: Step 1: The urban sludge is dried, crushed, and sieved. The purpose of drying is to remove the moisture in the sludge, and the particle size of the sludge is 20-40 meshes; Step 2: Mixing and forming Mix the prepared biochar with the treated sludge in a certain proportion. The added amounts of each raw material are as follows: the biochar prepared from Chinese medicine waste residue accounts for 5% of the total mass of the material; the sludge accounts for 40% of the total mass of the material; the clay accounts for 50% of the total mass of the material; the binder accounts for 5% of the total mass of the material. Add an appropriate amount of water to the mixed materials, stir evenly, and then use a mold to press them into a cylindrical shape; Step 3: Drying and heat treatment Transfer the formed filter material to an oven for drying. The drying temperature is 100 - 120 °C, and the drying time is 45 - 60 min to remove the moisture in the filter material and improve its strength and stability; Transfer the dried filter material to a muffle furnace for calcination for 2.5 - 3 h. The calcination temperature is 450 - 550 °C. After the calcination, naturally cool it to room temperature to obtain a semi-finished biofilter material; Step 4: Post-treatment and biofilm formation Immerse the heat-treated biofilter material in 5% hydrochloric acid by ultrasonic wave with a solid-liquid ratio of 1:10 for ultrasonic impregnation for 30 min, and then repeatedly rinse it with pure water until it is neutral, and dry it to obtain the final sample. This step can further remove the impurities on the surface of the filter material and improve its performance; Immerse the obtained semi-finished biofilter material in a microbial nutrient solution for 30 - 45 min and carry out microbial inoculation for 5 - 7 d to form a biofilm on the surface of the filter material to obtain a biofilm-formed biomass filter material. The molar ratio of carbon, nitrogen, and phosphorus in the nutrient solution is generally 100:5:1.

[0023] According to the large-pore concrete water permeability test method recommended by the Japan Concrete Industry Association, refer to the soil water permeability test method specified in JIS A 1218 to measure its water permeability coefficient, and refer to the China National Standard for the Determination of Water Absorption and Porosity of Asbestos Cement Products (GB / T 7019 - 2014) and the China National Standard for Building Materials - Water Permeable Bricks Industry Standard (JC / T 945 - 2005) to test the performance of the product. At the same time, test the COD removal rate and the average ammonia nitrogen removal rate. The test results are shown in Table 1. Example 2

[0024] Mix the prepared biochar with the treated sludge in a certain proportion. The added amounts of each raw material are as follows: the biochar prepared from Chinese medicine waste residue accounts for 10% of the total mass of the material; the sludge accounts for 50% of the total mass of the material; the clay accounts for 35% of the total mass of the material; the binder accounts for 5% of the total mass of the material. Add an appropriate amount of water to the mixed materials, stir evenly, and then use a mold to press them into a cylindrical shape.

[0025] In this embodiment, diatomite is selected as the binder. After mixing all the raw materials evenly, they are extruded into shape: after weighing all the raw materials according to the stated proportions, they are mixed in a dry grinding container. Due to the high-speed rotation of the blades, the raw materials are fully mixed. After the mixing is completed, the raw materials are poured into a mixing container, an appropriate amount of water is added, and they are fully stirred. The moisture content of the mixed material is controlled between 5% and 15%, and then it is extruded into shape on a granulator and sieved to obtain the filter material.

[0026] The remaining process steps are the same as those in Example 1. Example 3

[0027] The prepared biochar and the treated sludge are mixed in a certain proportion. The added amounts of each raw material are as follows: the biochar prepared from Chinese medicine residue accounts for 10% of the total mass of the material; the sludge accounts for 50% of the total mass of the material; the clay accounts for 30% of the total mass of the material; the binder accounts for 10% of the total mass of the material. An appropriate amount of water is added to the mixed material, and after stirring evenly, it is pressed into a cylindrical shape using a mold.

[0028] In this embodiment, diatomite is selected as the binder. After mixing all the raw materials evenly, they are extruded into shape: after weighing all the raw materials according to the stated proportions, they are mixed in a dry grinding container. Due to the high-speed rotation of the blades, the raw materials are fully mixed. After the mixing is completed, the raw materials are poured into a mixing container, an appropriate amount of water is added, and they are fully stirred. The moisture content of the mixed material is controlled between 5% and 15%, and then it is extruded into shape on a granulator and sieved to obtain the filter material.

[0029] The remaining process steps are the same as those in Example 1.

[0030] Table 1 shows the performance of the biological filter materials obtained in each example. Table 1. Performance of the biological filter materials obtained in Examples 1 - 3

Claims

1. A method for preparing biological filter material based on urban sludge and traditional Chinese medicine waste residue, characterized in that: The method includes: Step 1: Making biochar from waste residue of traditional Chinese medicine; Step 2: Mix the municipal sludge with the prepared biochar and other raw materials in proportion and press them into shape; Step 3: Dry and calcine the formed filter material, and after cooling, ultrasonically impregnate and form a film with hydrochloric acid.

2. According to claim 1, the biochar produced from waste residues of traditional Chinese medicine is prepared by filtering out most of the water from the waste residues of traditional Chinese medicine (such as Acanthopanax, Astragalus, Panax notoginseng, etc.), drying to constant weight, and then crushing, placing in a tubular furnace for pyrolysis into charcoal, introducing nitrogen after the pyrolysis until the inside of the furnace cavity cools to room temperature, and sieving to obtain biochar.

3. The municipal sludge according to claim 1 is mixed with various raw materials in proportion and pressed into shape, characterized in that The raw materials are urban sludge, clay, binder, and carbonized Chinese medicine waste residue, wherein the binder is diatomaceous earth; Preferably, the addition ratio of each raw material is: biochar prepared from traditional Chinese medicine waste residue accounts for 5%-10% of the total material mass; sludge accounts for 15%-70% of the total material mass; clay accounts for 30%-65% of the total material mass; binder accounts for 0.6%-10% of the total material mass. Add appropriate amount of water to the mixed material, stir evenly, and then use a mold to press it into a cylindrical shape.

4. According to claim 1, the filter material after forming is dried and calcined, and after cooling, ultrasonically impregnated with hydrochloric acid and then subjected to film formation treatment; Preferably, the formed filter material is transferred to an oven for drying at a temperature of 100-120°C for a drying time of 45-60 min, the dried filter material is transferred to a muffle furnace for calcination for 2.5-3 h at a calcination temperature of 450-550°C to obtain a semi-finished biofilter material, the heat-treated biofilter material is ultrasonically impregnated with 5% hydrochloric acid, the obtained semi-finished biofilter material is placed in a microbial nutrient solution and soaked for 30-45 min, and microbial inoculation is performed for 5-7 days to form a biofilm on the surface of the filter material to obtain a biofilm-forming biomass filter material.

5. According to claim 2, the specific steps of preparing biochar from waste residues of traditional Chinese medicine are as follows: After filtering out most of the moisture from the waste residue of traditional Chinese medicine, dry it to constant weight, crush the residue dried to constant weight to less than 2 mm, and put it into a tubular furnace for pyrolysis into charcoal. Before the start of pyrolysis, high-purity nitrogen at a flow rate of 100 mL / min is continuously introduced into the tubular furnace for 20 minutes to exhaust the air in the furnace chamber and form an oxygen-deficient environment. After the start of pyrolysis, the nitrogen flow rate is adjusted to 50 mL / min, and the furnace body is heated from room temperature to the target temperature of 450-700 °C at a heating rate of 10 °C / min, and maintained at the target temperature for 1 hour. After the pyrolysis process is completed, nitrogen is continued to be introduced until the quartz tube in the furnace chamber cools to room temperature. Subsequently, the biochar is taken out, ground and sieved through 60 mesh, and finally sealed for storage.

6. According to claims 3-4, the specific steps of preparing the biological filter material are as follows: Step 1: Dry, crush and screen the municipal sludge. The purpose of drying is to remove the moisture in the sludge. The particle size of the sludge is 20-40 mesh. Step 2: Mixing and molding The prepared biochar is mixed with the treated sludge in a certain proportion. The added amount of each raw material is as follows: the biochar prepared from the waste residue of traditional Chinese medicine accounts for 5%-10% of the total material mass; the sludge accounts for 15%-60% of the total material mass; the clay accounts for 30%-75% of the total material mass; the binder accounts for 0.6%-10% of the total material mass. Add appropriate amount of water to the mixed materials, stir evenly, and use a mold to press into a cylindrical shape. Step 3: Drying and heat treatment The formed filter material is transferred to an oven for drying at a temperature of 100-120°C for 45-60 minutes to remove moisture from the filter material and improve its strength and stability. The dried filter material is transferred to a muffle furnace and calcined for 2.5-3 h at a temperature of 450-550 °C. After calcination, it is naturally cooled to room temperature to obtain a semi-finished biological filter material. Step 4: Post-treatment and film formation The heat-treated biofilter material was ultrasonically impregnated with 5% hydrochloric acid at a solid-liquid ratio of 1:10 for 30 min, then repeatedly rinsed with pure water until neutral, and dried to obtain the final sample. This step can further remove impurities on the surface of the filter material and improve its performance. The obtained semi-finished biological filter material is placed in a microbial nutrient solution and soaked for 30-45 minutes, and microorganisms are inoculated for 5-7 days to form a biofilm on the surface of the filter material to obtain biofilm-forming biomass filter material. The molar ratio of carbon, nitrogen and phosphorus in the nutrient solution is generally 100:5:1.

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