Multichannel hollow porous ceramic biofilm carrier, method of making and use thereof

Abstract

The application provides a preparation method of a porous hollow multi-channel ceramic biofilm carrier and belongs to the technical field of sewage treatment.The application comprises the following steps: ceramic raw materials and a pore-forming agent are added into a solvent, uniformly mixed, and then grinded into ceramic slurry; a binder, a pore-forming agent and a dispersing agent are added into the ceramic slurry, stirred and dissolved to prepare ceramic slurry suspension; the ceramic slurry suspension prepared in step 1) is used to prepare a multi-channel hollow ceramic embryo through phase inversion method by using a multi-core spinning plate; and the hollow ceramic embryo is subjected to high-temperature sintering to prepare a multi-channel porous hollow ceramic biofilm carrier.The filling layer composed of the prepared short section porous hollow multi-channel ceramic biofilm carrier can form obvious anaerobic, anoxic and aerobic environments under the action of aeration, and the aerobic bacteria, anoxic bacteria and anaerobic bacteria outside the ceramic biofilm and in the channels can degrade organic matters, nitrogen and phosphorus in sewage, so that the ceramic biofilm carrier is an excellent sewage treatment filler.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a method for preparing a multi-channel hollow porous ceramic biofilm carrier, the multi-channel hollow porous ceramic biofilm carrier prepared by the method, and the application of the multi-channel hollow porous ceramic biofilm carrier in wastewater treatment. Background Technology

[0002] Biological aerated filters (BAF) are a popular water treatment technology internationally in recent years, attracting widespread attention in the wastewater treatment industry due to their high efficiency, energy saving, small footprint, and ease of operation. This technology utilizes microbial communities attached to the surface of the filter media to adsorb and oxidize pollutants in the water. Finally, the pores formed by the filter media remove suspended solids from the treated water, thus purifying the wastewater. The filter media, acting as the carrier of the biofilm, plays a central role in the biological aerated filter.

[0003] Some researchers have added zeolite to aerated biological filters to adsorb and treat low-to-medium concentration ammonia nitrogen wastewater (CN115057590A). Currently, the main fillers used in aerated biological filters at home and abroad are irregular fillers such as crushed stone, ceramsite, and activated carbon. The materials are mostly ceramic, metal, or plastic. Li Qianwei et al. (Li Qianwei, Zhou Xiaolu, Li Huan, et al. Preparation of fly ash ceramsite filler and performance study of its use as filler in aerated biological filters [J]. Chemical Industry and Engineering Progress, 2015, 34(9):3379-3382) prepared fly ash ceramsite by using fly ash as the main raw material and clay, dewatered sludge, desulfurized gypsum, etc. as auxiliary materials. Jiang Yuqin et al. (Jiang Yuqin, Li Jionghui, Fang Zhiguo. Influence of Porous Packing Material Characteristics on Biofilm Formation [J]. Environmental Science, 2020, 41(08):3684-3690.) compared several commonly used porous biological packing materials for biofilm formation (BAF), including sponge packing, hollow ball packing, spherical ceramsite, and zeolite, and found that spherical ceramsite is the most suitable packing material for BAF. Spherical ceramsite has good corrosion resistance, heat resistance, and surface wettability, and is inexpensive, so it is usually used as a packing material for BAF. However, the surface of this spherical packing material can only form an aerobic environment, and it is difficult to form anaerobic and hypoxic environments at the same time, so it is difficult to achieve the effect of simultaneous nitrogen and phosphorus removal. In the BAF system, the inner and outer pores of the selected porous filter material will gradually form a biofilm community composed of various microorganisms, which consume a large amount of organic matter through metabolism to achieve the purpose of water purification. Therefore, the performance of porous biological filter material has a decisive influence on the implementation effect of BAF process. Summary of the Invention

[0004] In view of this, to solve the technical problem that the surface of spherical packing materials in the prior art can only form an aerobic environment, and it is difficult to simultaneously form anaerobic and anoxic environments, thus making it difficult to achieve the effect of simultaneous nitrogen and phosphorus removal, on the one hand, this invention provides a method for preparing a multi-channel hollow porous ceramic biofilm carrier. This method uses a short-section hollow ceramic carrier with multiple channels in the middle and porous structures inside and out, which is filled into a biological treatment tank as a biofilm carrier. Under the aeration action of a bottom aeration device, anaerobic, anoxic, and aerobic environments can be formed simultaneously. This unique carrier constructs anaerobic, anoxic, and aerobic bacterial communities. When sewage flows through the short-section multi-channel hollow porous ceramic carrier packing layer, the aerobic, anoxic, and anaerobic bacteria on the ceramic carrier can simultaneously degrade organic matter, nitrogen, and phosphorus in the sewage, making it an excellent sewage treatment packing material.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing a multi-channel hollow porous ceramic biomembrane carrier includes the following steps:

[0007] 1) Preparation of ceramic film solution

[0008] Ceramic raw materials and pore-forming agents are added to a solvent, mixed evenly, and then ground into a ceramic slurry. A binder, pore-forming agent, and dispersant are added to the ceramic slurry and stirred to dissolve, thus obtaining a ceramic slurry suspension.

[0009] 2) Preparation of multi-channel hollow porous ceramic biomembrane carriers

[0010] The ceramic slurry suspension obtained in step 1) is used to prepare a multi-channel hollow ceramic preform by phase inversion using a multi-core spinning plate. The hollow ceramic preform is then sintered at high temperature to obtain a multi-channel hollow porous ceramic biofilm carrier.

[0011] Preferably, in step 1), by mass percentage, the ceramic raw material is 35-50 wt%, the binder is 5-15 wt%, the pore-forming agent is 1-10%, the dispersant is 1-5 wt%, the pore-forming agent is 3-7 wt%, and the solvent is 13-55 wt%.

[0012] Preferably, the ceramic raw material is one of tailings sand, Al2O3, SiO2 and ZrO2;

[0013] When the ceramic raw material is tailings sand, its mass percentage is 35-45 wt%.

[0014] When the ceramic raw material is Al2O3, its mass percentage is 35-50 wt%.

[0015] When the ceramic raw material is SiO2, its mass percentage is 40-50 wt%.

[0016] When the ceramic raw material is ZrO2, its mass percentage is 35-50 wt%.

[0017] The present invention also provides a multi-channel hollow porous ceramic biofilm carrier, which is prepared according to the above-described preparation method of the multi-channel hollow porous ceramic biofilm carrier.

[0018] Preferably, it has multiple hollow channels inside and a porous exterior.

[0019] Preferably, the multi-channel hollow porous ceramic biofilm carrier has an outer diameter of 2-3 mm, a length of 1-3 cm, and a channel diameter of 0.1-1 mm.

[0020] Preferably, it has 3 to 20 channels inside.

[0021] This invention also provides the preparation method of the above-mentioned multi-channel hollow porous ceramic biofilm carrier, the resulting multi-channel hollow porous ceramic biofilm carrier, or the application of the above-mentioned multi-channel hollow porous ceramic biofilm carrier in wastewater treatment.

[0022] Preferably, the multi-channel hollow porous ceramic biofilm carrier is filled in the upper part of the aeration device in the sewage treatment equipment.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This invention provides a method for preparing and applying a multi-channel hollow porous ceramic biofilm carrier. The prepared multi-channel hollow porous ceramic biofilm carrier is a short-segmented hollow ceramic biofilm carrier with many channels in the middle and many pores inside and out. The filling layer composed of the prepared short-segmented multi-channel hollow porous ceramic biofilm carrier has a high dissolved oxygen content on its outer surface under aeration. Aeration is difficult to penetrate the channels, while partial aeration and oxygenation can occur in the pores on the outer surface. This allows the short-segmented multi-channel hollow porous ceramic biofilm carrier to simultaneously create aerobic, anoxic, and anaerobic environments, achieving a growth environment for microorganisms that combines anaerobic, anoxic, and aerobic conditions. Both anoxic and anaerobic bacteria can degrade organic matter in wastewater, thus achieving simultaneous removal of nitrogen, phosphorus, and organic matter from wastewater. Furthermore, because of its small outer diameter and high filling rate, this multi-channel hollow porous ceramic biofilm carrier provides a large contact area between wastewater and the biofilm in wastewater treatment, offering more attachment points for different types of biofilms. Under the combined action of the three types of microorganisms, efficient removal of organic pollutants and nitrogen and phosphorus can be achieved. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the application of the short-section multi-channel hollow porous ceramic biofilm carrier prepared in this invention in wastewater treatment;

[0026] Figure 2 This is a schematic diagram of a multi-channel hollow porous ceramic biomembrane carrier prepared according to the present invention;

[0027] Figure 3 This is a schematic diagram of other multi-channel hollow porous ceramic biomembrane carriers prepared according to the present invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] Given that most ceramic materials used in existing BAF systems are granular, and although granular packing has a large specific surface area, it is difficult for it to form anoxic and anaerobic environments. This invention provides a method for preparing a multi-channel hollow porous ceramic biofilm carrier. The multi-channel hollow porous ceramic biofilm carrier prepared by this method can form distinct anaerobic, anoxic, and aerobic environments under aeration. This unique structure can be used to achieve a biological growth environment that combines anaerobic, anoxic, and aerobic conditions. When sewage flows through the ceramic biofilm packing layer, aerobic bacteria on the outside of the ceramic carrier, facultative anaerobic bacteria in the pores of the ceramic surface, and anaerobic bacteria in the channels can simultaneously degrade organic matter and nitrogen and phosphorus in the sewage, and achieve the separation of suspended solids in the treated water. This makes it an excellent sewage treatment packing material.

[0032] Specifically as follows:

[0033] A method for preparing a multi-channel hollow porous ceramic biomembrane carrier includes the following steps:

[0034] 1) Preparation of ceramic slurry suspension

[0035] Ceramic raw materials and pore-forming agents (preferably inorganic salt pore-forming agents, more preferably calcium carbonate as sintering pore-forming agents) are added to a solvent (preferably an organic solvent, more preferably N-dimethylacetamide) to dissolve and grind (preferably using a nano-grinding mill) to form a ceramic slurry. A binder (preferably a polymer binder, more preferably polyethersulfone), a dispersant (preferably a nano-powder dispersant) and a pore-forming agent (preferably a water-soluble pore-forming agent, more preferably polyethylene glycol, polyketone or polyvinylpyrrolidone) are added to the ceramic slurry and mixed evenly to obtain a ceramic slurry suspension.

[0036] 2) Preparation of multi-channel hollow porous ceramic biomembrane carriers

[0037] The ceramic slurry suspension obtained in step 1) was used to prepare a multi-channel hollow ceramic preform via a phase inversion method using a multi-core spinning plate; the solvent, pore-forming agent, and dispersant in the ceramic slurry suspension were replaced into the gel medium. The hollow ceramic preform was then subjected to high-temperature sintering, whereby the ceramic raw material was sintered into ceramic, and the pore-forming agent was burned off to form pores, directly preparing a short-section multi-channel hollow porous ceramic biofilm carrier;

[0038] In this invention, in step 1), by mass percentage, the ceramic raw material comprises 35-50 wt%, the binder 5-15 wt%, and the pore-forming agent 1-10 wt%, which form a hollow ceramic preform. The dispersant comprises 1-5 wt%, the pore-forming agent 3-7 wt%, and the solvent 13-55 wt%, all of which are dissolved into the gel medium during molding.

[0039] In this invention, the ceramic raw material is one of tailings sand, Al2O3, SiO2 and ZrO2;

[0040] When the ceramic raw material is tailings sand, its mass percentage is 35-45 wt%.

[0041] When the ceramic raw material is Al2O3, its mass percentage is 35-50 wt%.

[0042] When the ceramic raw material is SiO2, its mass percentage is 40-50 wt%.

[0043] When the ceramic raw material is ZrO2, its mass percentage is 35-50 wt%.

[0044] (Calculate the percentage of each substance based on the total of all materials being 100%. When different substances are selected for ceramic raw materials, the change in their mass percentage is balanced to 100% using solvent. If the material content is less than 100%, the solvent is added to balance to 100%.)

[0045] On the other hand, the present invention also provides a multi-channel hollow porous ceramic biofilm carrier, which is prepared according to the above-mentioned preparation method of the multi-channel hollow porous ceramic biofilm carrier.

[0046] like Figure 2-3 As shown, in this invention, it has multiple hollow channels in the middle and multiple pores inside and outside.

[0047] In this invention, the multi-channel hollow porous ceramic biofilm carrier has an outer diameter of 2-3 mm and a length of 1-3 cm, and the hollow channel has a diameter of 0.1-1 mm.

[0048] In this invention, there are 3 to 20 channels inside.

[0049] Furthermore, the present invention also provides the multi-channel hollow porous ceramic biofilm carrier prepared by the above-mentioned method, or the application of the above-mentioned multi-channel hollow porous ceramic biofilm carrier in wastewater treatment.

[0050] In this invention, the multi-channel hollow porous ceramic biofilm carrier is filled on top of the aeration device in the sewage treatment equipment.

[0051] Among them, such as Figure 1 As shown, the present invention provides a wastewater treatment device, which includes an aeration device and a filling layer composed of a multi-channel hollow porous ceramic biofilm carrier.

[0052] like Figure 1 As shown, the multi-channel hollow porous ceramic biofilm carrier of the present invention is used as a filler to fill the filler layer on top of the aeration device and is supported by a support layer. The aeration device is set inside the aerated biological filter, and the sewage equalization tank is connected to the aerated biological filter.

[0053] The technical solution of the present invention will be clearly and thoroughly described below with reference to specific embodiments.

[0054] Example 1

[0055] Using tailings sand, Al2O3, SiO2 and ZrO2 as ceramic raw materials, the ceramic raw materials and calcium carbonate as a pore-forming agent for sintering are added to N-N-dimethylacetamide and placed in a nano-grinding mill to prepare ceramic slurry. Polyethersulfone binder, sodium tripolyphosphate additive and polyethylene glycol pore-forming agent are added to the prepared ceramic slurry and stirred to prepare a ceramic slurry suspension.

[0056] The mass percentages of ceramic raw materials, organic solvents, polymer binders, inorganic salt pore-forming agents, water-soluble pore-forming agents, and nano-dispersants are 40wt%, 33wt%, 12wt%, 5wt%, 3wt%, 5wt%, and 2wt%, respectively.

[0057] Multichannel hollow ceramic preforms were prepared by phase inversion using a multicore spinning plate to prepare a ceramic slurry suspension; the hollow ceramic preforms were then sintered at high temperature in a muffle furnace to obtain a multichannel porous hollow ceramic biofilm carrier with a length of 2 cm.

[0058] The outer shell of the biological filter wastewater treatment equipment is made of plexiglass, fiberglass, carbon steel, or stainless steel. An aeration device, a support layer (a porous plate supporting a multi-channel hollow porous ceramic biofilm carrier), a water distribution device (uniform water distribution device), an overflow weir (for uniform effluent), and wastewater treatment control equipment (wastewater treatment equipment operation controller) are installed inside. The multi-channel porous hollow ceramic biofilm carrier prepared above is used as filler and filled to the top of the aeration device at a certain filling ratio to form a filler layer. Wastewater treatment is carried out under the control of the wastewater treatment control equipment.

[0059] Example 2

[0060] Same as Example 1, except that a multi-channel porous hollow ceramic biomembrane carrier with a length of 3 cm was prepared.

[0061] Example 3

[0062] Same as Example 1, except that a multi-channel porous hollow ceramic biomembrane carrier with a length of 1 cm was prepared.

[0063] Example 4

[0064] Same as Example 1, except that the ceramic raw materials, organic solvents, polymer binders, inorganic salt pore-forming agents, water-soluble pore-forming agents, and nano-dispersants are in the amounts of 50wt%, 10wt%, 15wt%, 5wt%, 10wt%, 5wt%, and 5wt%, respectively.

[0065] Example 5

[0066] Same as Example 1, except that the ceramic raw materials, organic solvents, polymer binders, inorganic salt pore-forming agents, water-soluble pore-forming agents, and nano-dispersants are in the amounts of 35wt%, 52wt%, 5wt%, 1wt%, 3wt%, 3wt%, and 1wt%, respectively.

[0067] Application Examples

[0068] The wastewater treatment equipment using the multi-channel hollow porous ceramic biofilm carrier developed in Implementation Cases 1-5 was used to treat simulated domestic wastewater. Simulated domestic wastewater with a specific composition was prepared. To reduce errors in water sample testing, pretreatment of both influent and effluent samples was necessary. The influent sample's water quality was measured as follows: COD concentration 380 mg / L, NH4+... + The concentration of -N was 30 mg / L, and the concentration of TP was 3.5 mg / L. Simulated domestic sewage was fed into a biofilter containing a multi-channel hollow porous ceramic membrane (using the multi-channel hollow porous ceramic membrane prepared in Example 1 as the carrier) through an inlet valve. The sewage entering the aerated biofilter was mixed using a stirrer, and the aeration pressure was adjusted using a gas flow meter. Through continuous oxygenation, the unique structure of the multi-channel hollow porous ceramic biofilm carrier created distinct anaerobic, anoxic, and aerobic environments. Simultaneously, the high filling rate of the porous hollow multi-channel ceramic biofilm carrier provided attachment points for various types of microorganisms. Aerobic, anoxic, and anaerobic bacteria were cultivated on the outside and inside the channels of the ceramic biofilm carrier. When sewage flowed through the ceramic biofilm packing layer, under the combined action of the mixed bacterial species, after a period of operation, the effluent water quality was: COD concentration 21 mg / L, NH4+ concentration 3.5 mg / L. + The concentration of -N was 4.7 mg / L, the concentration of TP was 0.37 mg / L, and the concentration of SS was 6 mg / L.

[0069] Example 2

[0070] Similar to Example 1, except that a 3cm long multi-channel porous hollow ceramic biofilm was used as the carrier. The influent was the same as in Example 1, and the effluent quality was COD concentration of 26mg / L and NH4+ concentration of 100mg / L. + The concentration of -N was 5.8 mg / L, the concentration of TP was 0.41 mg / L, and the concentration of SS was 7.

[0071] Example 3

[0072] Same as Example 1, except that a multi-channel porous hollow ceramic biofilm carrier with a length of 1 cm is used. The influent is the same as in Example 1, and the effluent quality is COD concentration of 25 mg / L and NH4+ concentration of 1 cm. + The concentration of -N was 4.0 mg / L, the concentration of TP was 0.28 mg / L, and the concentration of SS was 5.

[0073] Example 4

[0074] Similar to Example 1, except that the formulation for the multi-channel porous hollow ceramic carrier is as follows: ceramic raw materials, organic solvent, polymer binder, inorganic salt pore-forming agent, water-soluble pore-forming agent, and nano-dispersant at concentrations of 50wt%, 10wt%, 15wt%, 5wt%, 10wt%, 5wt%, and 5wt%, respectively. The influent is the same as in Example 1, and the effluent has a COD concentration of 29 mg / L and an NH4+ concentration of... + The concentration of -N was 6 mg / L, the concentration of TP was 0.20 mg / L, and the concentration of SS was 4.

[0075] Example 5

[0076] Similar to Example 1, except that the formulation for the multi-channel porous hollow ceramic carrier is as follows: ceramic raw materials, organic solvent, polymer binder, inorganic salt pore-forming agent, water-soluble pore-forming agent, and nano-dispersant at 35wt%, 52wt%, 5wt%, 1wt%, 3wt%, 3wt%, and 1wt% respectively. The influent is the same as in Example 1, and the effluent has a COD concentration of 20 mg / L and NH4+ concentration of... + The concentration of -N was 4 mg / L, the concentration of TP was 0.30 mg / L, and the concentration of SS was 5.

[0077] Comparative Example 1

[0078] Spherical ceramics from Jiang Yuqin et al. (Jiang Yuqin, Li Jionghui, Fang Zhiguo. Influence of porous packing characteristics on biofilm formation [J]. Environmental Science, 2020, 41(08):3684-3690.) were selected as Comparative Example 1. Wastewater prepared in the laboratory was added, with MLSS of 0 mg / L, COD of 50 mg / L, and ammonia nitrogen of 25 mg / L. The multi-channel porous hollow ceramic biofilm carrier from Application Example 1 was used instead of the ceramsite carrier. Based on the changes in the removal load of ammonia nitrogen and COD by the new carrier over time, after 2 hours of operation of the wastewater treatment equipment, the average removal of ammonia nitrogen was 40.5 g / m³. 3 The average COD removal load was 130.6 g / m³. 3 The removal rate was higher than the average removal load of 33.47 g / m³ for ammonia nitrogen and COD in Comparative Example 1. 3 .h and 120.75g / m 3 .h

[0079] Although the technical solutions of the present invention have been described and enumerated in detail, it should be understood that modifications to the above embodiments or the adoption of equivalent alternatives are obvious to those skilled in the art. Such modifications or improvements made without departing from the spirit of the present invention are all within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a multi-channel hollow porous ceramic biomembrane carrier, characterized in that, Includes the following steps: 1) Preparation of ceramic film solution Ceramic raw materials and pore-forming agents are added to a solvent, mixed evenly, and then ground into a ceramic slurry. A binder, pore-forming agent, and dispersant are added to the ceramic slurry and stirred to dissolve, thus obtaining a ceramic slurry suspension. 2) Preparation of multi-channel hollow porous ceramic biomembrane carriers The ceramic slurry suspension obtained in step 1) is used to prepare a multi-channel hollow ceramic preform via a phase inversion method using a multi-core spinning plate. The hollow ceramic preform is then subjected to high-temperature sintering to obtain a multi-channel hollow porous ceramic biofilm carrier with multiple hollow channels inside and a porous exterior. The multi-channel hollow porous ceramic biofilm carrier has an outer diameter of 2-3 mm, a length of 1-3 cm, and a channel diameter of 0.1-1 mm. In step 1), based on a total material weight of 100 wt%, the ceramic raw material comprises 35–50 wt%, the binder 5–15 wt%, the pore-forming agent 1–10 wt%, the dispersant 1–5 wt%, the pore-forming agent 3–7 wt%, and the solvent 13–55 wt%. The ceramic raw material is one of tailings sand, Al2O3, SiO2 and ZrO2; When the ceramic raw material is tailings sand, its mass percentage is 35-45 wt%. When the ceramic raw material is Al2O3, its mass percentage is 35-50 wt%. When the ceramic raw material is SiO2, its mass percentage is 40-50 wt%. When the ceramic raw material is ZrO2, its mass percentage is 35-50 wt%.

2. A multi-channel hollow porous ceramic biofilm carrier, characterized in that, The multi-channel hollow porous ceramic biofilm carrier was prepared according to the method described in claim 1.

3. The multi-channel hollow porous ceramic biomembrane carrier according to claim 2, characterized in that, It has 3 to 20 channels inside.

4. The application of the multi-channel hollow porous ceramic biofilm carrier as described in claim 2 or 3 in wastewater treatment.

5. The application according to claim 4, characterized in that, The multi-channel hollow porous ceramic biofilm carrier is filled in the upper part of the aeration device in the sewage treatment equipment.

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