Biomass filler and method for producing same, and constructed wetland

Abstract

The application provides a biomass filler and a preparation method thereof and an artificial wetland. The preparation method of the biomass filler comprises the following steps: mixing biomass waste residue powder and a metal ion solution to prepare a suspension; performing a calcination treatment on the suspension to prepare filler powder; and mixing the filler powder and an additive, and performing an expansion treatment to prepare the biomass filler. The above method of the application prepares the biomass filler based on the waste biomass waste residue powder, realizes the resource utilization of waste, reduces environmental pollution, reduces the preparation cost of the filler, and the prepared biomass filler has good water purification capacity.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a biomass filler and its preparation method, and constructed wetlands. Background Technology

[0002] Constructed wetlands are a common type of ecological engineering that simulates the functions of natural wetlands, playing a vital role in purifying water quality and maintaining ecological balance. The construction of constructed wetlands not only helps improve watershed water quality and the ecological environment but also effectively realizes the resource utilization of wastewater.

[0003] The influent to constructed wetlands is primarily wastewater effluent from wastewater treatment plants, typically classified as Class A. However, the water quality requirements for surface water discharge are usually higher than Class IV. This means there is a significant difference between the influent quality and the final water quality required for surface water discharge. To ensure the effluent quality meets the requirements for surface water discharge, constructed wetlands need a high capacity for water quality improvement. However, traditional constructed wetlands suffer from problems such as substandard total nitrogen levels in the effluent and insufficient purification efficiency.

[0004] Packing material is a core component of constructed wetlands and has a significant impact on the purification function of the constructed wetland system. Traditional constructed wetland packing materials include gravel and volcanic rock, but gravel has low adsorption capacity, and volcanic rock is expensive, making it difficult to simultaneously meet the requirements of low cost and good decontamination effect. Summary of the Invention

[0005] Based on this, one or more embodiments of this application provide a method for preparing biomass fillers using biomass waste residue, as well as corresponding biomass fillers and constructed wetlands.

[0006] According to a first aspect of the embodiments of this application, a method for preparing biomass filler is provided, comprising the following steps:

[0007] A suspension was prepared by mixing biomass waste residue powder with a metal ion solution;

[0008] The suspension is subjected to calcination to prepare filler powder;

[0009] The biomass filler is prepared by mixing the filler powder with additives and then undergoing an expansion process.

[0010] In some embodiments, the metal ions are derived from one or more of Fe3O4 and MnO2;

[0011] Furthermore, the mass ratio of the biomass waste powder to the metal ions is 2:(0.01~0.05).

[0012] In some embodiments, before mixing the biomass waste powder with the metal ion solution, the following step is further included: ultrasonic treatment of the biomass waste powder;

[0013] Optionally, the frequency of the ultrasonic treatment is 140kHz~160kHz, and the duration is 0.8h~1.2h;

[0014] Optionally, after ultrasonic treatment, the method further includes the following step: drying the biomass waste powder;

[0015] Further optionally, the drying temperature is 100℃~110℃.

[0016] In some embodiments, the method for preparing the biomass waste powder includes the following steps: sequentially crushing and grinding the biomass waste from the power plant to prepare the biomass waste powder;

[0017] Optionally, after crushing and before grinding, the following steps are also included: acid leaching the crushed power plant biomass waste residue with an acid solution;

[0018] Further optionally, the acid solution includes one or more of phosphoric acid solution, sulfuric acid solution and nitric acid solution;

[0019] Further optionally, the mass ratio of the acid solution to the pulverized biomass waste residue from the power plant is (1.5~2.5):1.

[0020] In some embodiments, the particle size of the biomass waste powder is less than or equal to 125 μm; and / or,

[0021] The biomass filler has a particle size of 3cm to 5cm; and / or,

[0022] The firing temperature is 180℃~220℃, and the time is 3h~5h.

[0023] In some embodiments, the additives include pumping agents, foaming agents, cement, and expanding agents;

[0024] Optionally, the mass ratio of the filler powder, water, pumping agent, foaming agent and cement is (100~200):(240~260):(20~30):(45~55):(450~550).

[0025] Optionally, the amount of the expanding agent added is 4wt% to 6wt%, based on the sum of the masses of the filler powder, the water, the pumping agent, the foaming agent and the cement.

[0026] In some embodiments, the method of mixing biomass waste powder with metal ion solution includes stirring;

[0027] Optionally, the stirring speed is 100 r / min to 260 r / min.

[0028] According to a second aspect of the embodiments of this application, a biomass packing material is provided, which is prepared by the above-described method for preparing biomass packing material.

[0029] According to a third aspect of the embodiments of this application, an artificial wetland is provided, comprising a sand and gravel layer, a first artificial gravel layer, a biomass filler layer, and a second artificial gravel layer arranged in sequence.

[0030] The biomass packing layer includes the aforementioned biomass packing.

[0031] In some embodiments, the sand and gravel layer comprises sand and gravel with a particle size of 0.2 cm to 0.5 cm; and / or,

[0032] The first artificial gravel layer comprises first artificial gravel with a particle size of 1 cm to 3 cm; and / or,

[0033] The second artificial gravel layer includes second artificial gravel with a particle size of 1 cm to 3 cm; and / or,

[0034] The thickness of the sand and gravel layer is 8cm to 12cm; and / or,

[0035] The thickness of the first artificial gravel layer is 8cm to 12cm; and / or,

[0036] The thickness of the biomass filler layer is 50cm~70cm; and / or,

[0037] The thickness of the second artificial gravel layer is 18cm to 22cm.

[0038] Compared with traditional technologies, this application has the following advantages:

[0039] This application uses a metal ion solution to treat waste biomass residue powder, and through a calcination process, loads the metal ions in the solution onto the biomass residue powder. The metal ions act as a catalyst to promote micropore formation, thereby increasing the micropore porosity of the packing powder and the content of oxygen-containing groups such as hydroxyl and carboxyl groups on the surface of the packing powder; thus, it enhances the adsorption capacity of the biomass packing for pollutants. Simultaneously, mixing the packing powder with additives and then performing an expansion treatment further increases the porosity and adsorption area of ​​the biomass packing. The above method of this application, based on waste biomass residue powder, not only achieves resource utilization of waste, reduces environmental pollution, and lowers the cost of packing preparation, but also produces biomass packing with excellent water purification capabilities. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the specific embodiments of this application, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0041] Figure 1 This is a schematic diagram of the longitudinal section of an artificial wetland prepared according to one embodiment of this application.

[0042] Explanation of reference numerals in the attached drawings: 1. Sand and gravel layer; 2. First artificial gravel layer; 3. Biomass filler layer; 4. Second artificial gravel layer. Detailed Implementation

[0043] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise specifically stated, all raw materials, reagents, instruments, and equipment used in this application are commercially available or can be prepared by existing methods.

[0045] The terms "and / or," "or / and," and "and / or" as used herein include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that in this application, the technical solution undoubtedly includes technical solutions connected by "logical AND," and also undoubtedly includes technical solutions connected by "logical OR." For example, "A and / or B" includes three parallel solutions: A, B, and A+B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, a technical solution that is connected by "logical OR"), as well as any and all combinations of A, B, C, and D, that is, combinations of any two or three of A, B, C, and D, and also combinations of all four of A, B, C, and D (that is, a technical solution that is connected by "logical AND").

[0046] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0047] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0048] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0049] In this document, terms such as “preferred,” “better,” “more suitable,” and “ideal” are merely used to describe implementation methods or examples that achieve better results, and should be understood not to limit the scope of protection of this application.

[0050] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0051] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0052] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0053] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0054] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0055] In this application, %(w / w) and wt% both represent weight percentage, %(v / v) refers to volume percentage, and %(w / v) refers to mass-volume percentage.

[0056] Some embodiments of this application provide a method for preparing biomass filler, comprising the following steps:

[0057] A suspension was prepared by mixing biomass waste residue powder with a metal ion solution;

[0058] The suspension was calcined to prepare filler powder;

[0059] Biomass fillers are prepared by mixing filler powder with additives and then undergoing expansion treatment.

[0060] Biomass waste residue is the main waste generated by biomass power plants from burning biomass fuels such as straw and wood. Currently, a large amount of biomass waste residue in power plants is not properly disposed of. The inventors of this application have discovered through research that the reuse of biomass waste residue and its application in constructed wetland filling systems has broad prospects.

[0061] In some embodiments, the particle size of the biomass filler is 3cm to 5cm. As an example, the particle size of the biomass filler can be 3.0cm, 3.1cm, 3.2cm, 3.3cm, 3.4cm, 3.5cm, 3.6cm, 3.7cm, 3.8cm, 3.9cm, 4.0cm, 4.1cm, 4.2cm, 4.3cm, 4.4cm, 4.5cm, 4.6cm, 4.7cm, 4.8cm, 4.9cm, 5.0cm, or any value within the range formed by any two of the above values.

[0062] In some embodiments, the metal ions are derived from one or more of Fe3O4 and MnO2. Further, the metal ions are derived from Fe3O4.

[0063] It is understandable that mixing biomass waste powder with metal ion solution and then subjecting it to calcination allows the metal ions to be loaded onto the biomass waste powder, thereby increasing the micropore porosity of the filler powder and increasing the content of oxygen-containing groups such as hydroxyl and carboxyl groups on the surface of the filler powder; thus improving the adsorption capacity of biomass filler for pollutants.

[0064] In some embodiments, the mass ratio of biomass waste powder to metal ions is 2:(0.01~0.05). As an example, the mass ratio of biomass waste powder to metal ions can be 2:0.01, 2:0.02, 2:0.03, 2:0.04, 2:0.05, or any value within the range of any two of the above ratios.

[0065] Furthermore, the mass ratio of biomass waste powder to metal ions is 2:(0.03~0.05).

[0066] Furthermore, the mass ratio of biomass waste powder to metal ions is 2:0.03.

[0067] In some embodiments, the solvent for the metal ion solution is a hydrochloric acid solution.

[0068] In some embodiments, the method of mixing biomass waste powder with metal ion solution includes stirring.

[0069] In some examples, the stirring speed is 100 r / min to 260 r / min.

[0070] As an example, the stirring speed can be 100 r / min, 110 r / min, 120 r / min, 130 r / min, 140 r / min, 150 r / min, 160 r / min, 170 r / min, 180 r / min, 190 r / min, 200 r / min, 210 r / min, 220 r / min, 230 r / min, 240 r / min, 250 r / min, 260 r / min, or any value within the range formed by any two of the above points.

[0071] It is understandable that when mixing biomass waste powder with metal ion solution, stirring can effectively increase the contact between biomass waste powder and metal ions, further enhance the doping efficiency, and thus increase the metal doping rate in biomass waste.

[0072] In some embodiments, before mixing the biomass waste powder with the metal ion solution, the following step is included: ultrasonic treatment of the biomass waste powder.

[0073] In some examples, the frequency of ultrasonic treatment is 140kHz to 160kHz, and the duration is 0.8h to 1.2h. For example, the frequency of ultrasonic treatment can be 140kHz, 141kHz, 142kHz, 143kHz, 144kHz, 145kHz, 146kHz, 147kHz, 148kHz, 149kHz, 150kHz, 151kHz, 152kHz, 153kHz, 154kHz, 155kHz, 156kHz, 157kHz, 158kHz, 159kHz, or 160kHz, or any value within the range of any two of the above values; the duration of ultrasonic treatment can be 0.8h, 0.9h, 1.0h, 1.1h, or 1.2h, or any value within the range of any two of the above values.

[0074] Furthermore, the ultrasonic treatment frequency was 150 kHz, and the duration was 1 hour.

[0075] It is understandable that ultrasonic treatment of biomass waste powder can increase its porosity and specific surface area, thus making it more suitable for metal doping.

[0076] In some examples, the following step is included after ultrasonic treatment: drying the biomass waste powder.

[0077] In some examples, the drying temperature is 100℃~110℃. As an example, the drying temperature can be 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, or any value within the range formed by any two of the above points.

[0078] Furthermore, the drying temperature is 150°C.

[0079] In some embodiments, the method for preparing biomass waste powder includes the following steps: sequentially crushing and grinding biomass waste from power plants to prepare biomass waste powder.

[0080] Understandably, biomass waste from power plants typically includes components such as SiO2, Al2O3, CaO, and MgO; among which, the SiO2 content is approximately 55.6%, the Al2O3 content is approximately 11.56%, the CaO content is approximately 7.67%, and the MgO content is approximately 1.46%. When the SiO2 content is not less than 50%, the biomass packing material made from this waste can effectively handle NH4+. + It exhibits excellent selective adsorption performance; and elements such as Mg, Ca, and Al readily react with phosphate ions to form phosphate precipitates, thereby removing phosphorus from wastewater.

[0081] In some embodiments, the particle size of the biomass waste powder is less than or equal to 125 μm. As an example, the particle size of the biomass waste powder can be 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, 105 μm, 110 μm, 115 μm, 120 μm, 125 μm, or any value within the range formed by any two of the above values.

[0082] Furthermore, the particle size of the biomass waste powder is 1μm~125μm.

[0083] In some embodiments, after pulverizing and before grinding, the following steps are also included:

[0084] Deionized water is used to wash and dry the pulverized biomass waste residue from the power plant.

[0085] In some embodiments, after pulverizing and before grinding, the following steps are also included:

[0086] The crushed biomass waste from the power plant was treated with an acid leaching solution.

[0087] In some examples, the acid solution includes one or more of phosphoric acid solution, sulfuric acid solution, and nitric acid solution.

[0088] Further, the acid solution is selected from phosphoric acid solution; optionally, the mass concentration of the phosphoric acid solution is 85%.

[0089] In some examples, the mass ratio of acid solution to pulverized biomass waste from the power plant is (1.5~2.5):1. As examples, the mass ratio of acid solution to pulverized biomass waste from the power plant can be 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, or any value within the range of any two of the above ratios.

[0090] Furthermore, the mass ratio of the acid solution to the pulverized biomass waste residue from the power plant is 2:1.

[0091] Understandably, acid leaching of biomass waste can reduce its ash and other impurity content, thereby increasing the specific surface area and total pore volume of the biomass waste.

[0092] In some embodiments, the firing temperature is 180℃~220℃, and the time is 3h~5h. As an example, the firing temperature can be 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃, 220℃, or any value within the range formed by any two of the above values. The firing time can be 3.0h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h, 4.0h, 4.1h, 4.2h, 4.3h, 4.4h, 4.5h, 4.6h, 4.7h, 4.8h, 4.9h, 5.0h, or any value within the range formed by any two of the above values.

[0093] Furthermore, the firing temperature is 200℃ and the time is 4 hours.

[0094] In some embodiments, the additives include pumping agents, foaming agents, cement, and expanding agents.

[0095] In some examples, the pumping agent was purchased from Hongzhida, product model 25kg / JC / 473-2001.

[0096] In some examples, the foaming agent was purchased from McLean, product model CAS: 80-17-1.

[0097] In some examples, the expanding agent is selected from calcium sulfoaluminate. Furthermore, the purity of calcium sulfoaluminate is greater than or equal to 99%.

[0098] In some embodiments, the step of mixing the filler powder with the additives includes: mixing the filler powder, water, pumping agent, foaming agent and cement to prepare a mixture; and then mixing the mixture with an expanding agent.

[0099] In some examples, the mass ratio of filler powder, water, pumping agent, foaming agent and cement is (100~200):(240~260):(20~30):(45~55):(450~550).

[0100] Understandably, before mixing the filler powder, water, pumping agent, foaming agent, and cement, the following steps are also included: dissolving the pumping agent and foaming agent separately in water.

[0101] It should be noted that in the above mass ratios, filler powder, pumping agent, and foaming agent all refer to the mass of solid substances.

[0102] As an example, the mass fraction of the filler powder can be 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, or 200 parts, or any value within the range formed by any two of the above points; the mass fraction of water can be 240 parts, 245 parts, 250 parts, 255 parts, or 260 parts, or any value within the range formed by any two of the above points; the mass fraction of the pumping agent can be 20 parts, 22 parts, 24 parts, or 26 parts. The mass ratio of filler powder, water, pumping agent, foaming agent, and cement can be any of the above two values: 28 parts, 30 parts, or any value within the range formed by any two of the above points; the mass ratio of foaming agent can be 45 parts, 47 parts, 49 parts, 51 parts, 53 parts, 55 parts, or any value within the range formed by any two of the above points; the mass ratio of cement can be 450 parts, 460 parts, 470 parts, 480 parts, 490 parts, 500 parts, 510 parts, 520 parts, 530 parts, 540 parts, 550 parts, or any value within the range formed by any two of the above points. In other words, the mass ratio of filler powder, water, pumping agent, foaming agent, and cement can be any of the above-mentioned mass ratios.

[0103] In some examples, the amount of expansive agent added is 4wt% to 6wt% based on the sum of the mass of filler powder, water, pumping agent, foaming agent and cement.

[0104] As an example, based on the sum of the masses of filler powder, water, pumping agent, foaming agent, and cement, the amount of expansive agent added can be 4.0wt%, 4.2wt%, 4.4wt%, 4.6wt%, 4.8wt%, 5.0wt%, 5.2wt%, 5.4wt%, 5.6wt%, 5.8wt%, 6.0wt%, or any value within the range formed by any two of the above points.

[0105] In some examples, the puffing process is static puffing.

[0106] In some examples, the puffing process takes 7 to 10 days. As an example, the puffing process can take 7, 8, 9, or 10 days, or any value within the range of any two of the above points.

[0107] In some embodiments, after the expansion process, the following step is included: crushing the mixture of filler powder and additives.

[0108] It is understandable that crushing can ensure that the particle size of the final biomass filler is within a specific range.

[0109] The method for preparing biomass filler in this application modifies biomass waste residue, an industrial waste, to produce biomass filler. This not only realizes the resource utilization of waste and reduces environmental pollution, but also effectively reduces the preparation cost of filler, providing a more economical and efficient approach for the construction and maintenance of constructed wetlands.

[0110] Meanwhile, under anaerobic conditions, metal ions combined with biomass waste residue are used as electron donors for denitrification. Nitrate ions replace oxygen as electron acceptors, and the nitrogen in nitrate ions is reduced to nitrogen gas, thereby achieving the removal of total nitrogen from wastewater.

[0111] Compared with traditional constructed wetland fillers, the biomass filler of this application has higher porosity and specific surface area, thereby enhancing contact with pollutants and improving the total nitrogen removal rate, achieving a significant improvement in nitrogen and phosphorus removal performance. In this way, the problem of non-compliance of total nitrogen in the effluent of traditional constructed wetlands is effectively improved, while the stability of effluent water quality during the low temperature period in winter is improved, and the overall water purification efficiency is enhanced.

[0112] In some other embodiments of this application, a biomass packing material is provided, which is prepared by the above-described method for preparing biomass packing material.

[0113] The biomass filler prepared by the above method has a good denitrification effect on wastewater; and its particle size is moderate, making it less prone to loss in constructed wetland systems, thus making it suitable as a filler for constructed wetland systems.

[0114] Other embodiments of this application provide an artificial wetland, such as... Figure 1 As shown, it includes a sand and gravel layer 1, a first artificial gravel layer 2, a biomass filler layer 3, and a second artificial gravel layer 4, which are stacked in sequence.

[0115] The raw materials for the biomass packing layer 34 include the aforementioned biomass packing.

[0116] In some embodiments, the thickness of the sand and gravel layer 1 is 8cm to 12cm. As an example, the thickness of the sand and gravel layer 1 can be 8cm, 9cm, 10cm, 11cm, or 12cm, or any value within the range formed by any two of the above points.

[0117] In some embodiments, the thickness of the first artificial gravel layer 2 is 8cm to 12cm. As an example, the thickness of the first artificial gravel layer 2 can be 8cm, 9cm, 10cm, 11cm, or 12cm, or any value within the range formed by any two of the above points.

[0118] In some embodiments, the thickness of the biomass filler layer 3 is 50cm to 70cm. As an example, the thickness of the biomass filler layer 3 can be 0cm, 52cm, 54cm, 56cm, 58cm, 60cm, 62cm, 64cm, 66cm, 68cm, 70cm, or any value within the range formed by any two of the above points.

[0119] In some embodiments, the thickness of the second artificial gravel layer 4 is 18cm to 22cm. As an example, the thickness of the second artificial gravel layer 4 can be 18cm, 19cm, 20cm, 21cm, or 22cm, or any value within the range formed by any two of the above points.

[0120] In some embodiments, the sand and gravel layer 1 comprises sand and gravel with a particle size of 0.2 cm to 0.5 cm. As an example, the particle size of the sand and gravel can be 0.2 cm, 0.3 cm, 0.4 cm, 0.5 cm, or any value within the range formed by any two of the above values.

[0121] In some embodiments, the first artificial gravel layer 2 includes first artificial gravel with a particle size of 1 cm to 3 cm.

[0122] In some embodiments, the second artificial gravel layer 4 includes second artificial gravel with a particle size of 1 cm to 3 cm.

[0123] As an example, the particle size of the first artificial gravel and the second artificial gravel can each be independently 1.0cm, 1.2cm, 1.4cm, 1.6cm, 1.8cm, 2.0cm, 2.2cm, 2.4cm, 2.6cm, 2.8cm, 3.0cm, or any value within the range formed by any two of the above point values.

[0124] The artificial wetland constructed using the aforementioned biomass filler material can achieve efficient wastewater purification within a short hydraulic retention time, meeting the Class V surface water standard, which is beneficial to improving watershed water quality and protecting the ecological environment.

[0125] The present application will be further described below with reference to specific embodiments and comparative examples, but these should not be construed as limiting the scope of protection of the present application. Unless otherwise specified, the raw materials involved in the following specific embodiments are all commercially available, the instruments used are all commercially available, and the processes involved are conventionally selected by those skilled in the art unless otherwise specified.

[0126] Example 1

[0127] S1: The obtained biomass waste residue from the power plant is put into a pulverizer and crushed. After being repeatedly washed with deionized water, it is dried at 105℃. After drying, it is taken out and cooled to room temperature. It is then ground using an agate mortar and passed through a 120-mesh sieve to obtain biomass waste residue powder.

[0128] S2: The above-mentioned biomass waste powder is mixed with Fe3O4 solution to obtain a suspension. This suspension is then poured into a porcelain crucible and fired in a muffle furnace at 200℃ for 4 hours. After removal and cooling, the filler powder is obtained. The mass ratio of biomass waste powder to Fe ions is 2:0.03.

[0129] S3: Mix the filler powder, water, pumping agent (purchased from Hongzhida, model 25kg / JC / 473-2001), foaming agent (purchased from Maclean, model CAS: 80-17-1), and cement in a mass ratio of 150:250:25:50:500. After thorough mixing, add 5wt% of expanding agent and mix thoroughly again. Once all components are fully combined, place the mixture in a mold and allow it to expand. Curing and standing for 7 days is then carried out. After curing, crush the mixture to obtain biomass filler with a particle size of 3cm~5cm.

[0130] S4: Wastewater pretreatment. Wastewater is fed into a pre-sedimentation tank, and polyaluminum chloride is added at a dosage of 5 mg / L. The mixture is then stirred at 25°C for 15 min. The supernatant is then passed into a filter tank and filtered using a 50 μm filter. Finally, the pH of the supernatant is adjusted to 7.2 using a 15% H2SO4 solution. The pretreated wastewater has a chemical oxygen demand (COD) of 50 mg / L, a biochemical oxygen demand (BOD) of 10 mg / L, a total phosphorus content of 0.3 mg / L, and a total nitrogen content of 15 mg / L.

[0131] S5: Construct an artificial wetland system, comprising, from bottom to top, a 10cm thick sand and gravel layer 1, a 10cm thick first artificial gravel layer 2, a 60cm thick biomass filler layer 3, and a 20cm thick second artificial gravel layer 4. The raw material for sand and gravel layer 1 includes sand and gravel with a particle size of 0.2cm to 0.5cm. The raw material for both the first artificial gravel layer 2 and the second artificial gravel layer 4 is artificial gravel with a particle size of 1cm to 3cm. The raw material for biomass filler layer 3 includes biomass filler with a particle size of 3cm to 5cm prepared in S1 to S3.

[0132] The pretreated wastewater from S4 was fed into the constructed wetland system built from S5. The reactor temperature was controlled at 25℃, the hydraulic retention time at 24h, and the hydraulic loading at 0.5m. 3 ·m 2 ·d -1 And simulate natural lighting environment.

[0133] Example 2

[0134] This embodiment is basically the same as Example 1, except that step S1 is different; the remaining steps and parameters are the same as in Example 1. Specifically, step S1 in this embodiment includes the following steps:

[0135] The obtained biomass waste from the power plant was crushed in a pulverizer. The crushed biomass waste was then mixed with an 85% phosphoric acid solution and thoroughly impregnated; the mass ratio of phosphoric acid solution to crushed biomass waste was 2:1. After impregnation, the residue was repeatedly washed with deionized water and dried at 105℃. After drying, it was removed and allowed to air dry at room temperature. It was then ground using an agate mortar and pestle and passed through a 120-mesh sieve to obtain biomass waste powder.

[0136] Example 3

[0137] This embodiment is basically the same as Example 1, except that step S1 is different; the remaining steps and parameters are the same as in Example 1. Specifically, step S1 in this embodiment includes the following steps:

[0138] The obtained biomass waste from the power plant was crushed in a pulverizer. The crushed biomass waste was then mixed with an 85% phosphoric acid solution and thoroughly impregnated; the mass ratio of phosphoric acid solution to crushed biomass waste was 2:1. After impregnation, the residue was repeatedly washed with deionized water and dried at 105℃. After drying, it was removed and allowed to air dry at room temperature. It was then ground using an agate mortar and passed through a 120-mesh sieve to obtain biomass waste powder. The ground biomass waste powder was redispersed in water and ultrasonically treated at 150kHz for 1 hour, and then dried again at 105℃.

[0139] Example 4

[0140] This embodiment is basically the same as Example 3, except that step S2 is different; the remaining steps and parameters are the same as in Example 3. Specifically, step S2 in this embodiment includes the following steps:

[0141] The ultrasonically treated and dried biomass waste powder was mixed with Fe3O4 solution and magnetically stirred at 200 r / min for 15 min to obtain a suspension. This suspension was then poured into a porcelain crucible and fired in a muffle furnace at 200℃ for 4 h. After cooling, the filler powder was obtained. The mass ratio of biomass waste powder to Fe ions was 2:0.03.

[0142] Example 5

[0143] This embodiment is basically the same as Example 4, except that step S3 is different; the remaining steps and parameters are the same as in Example 4. Specifically, step S3 in this embodiment includes the following steps:

[0144] The filler powder, water, pumping agent (purchased from Hongzhida, model 25kg / JC / 473-2001), foaming agent (purchased from Maclean, model CAS: 80-17-1), and cement were mixed in a mass ratio of 100:250:25:50:500. After thorough mixing, 5wt% of expanding agent (calcium sulfoaluminate, purity ≥99%) was added, and the mixture was stirred thoroughly again. After all components were fully combined, the mixture was placed in a mold and allowed to expand for 7 days. After curing, the mixture was crushed to obtain biomass filler with a particle size of 3cm~5cm.

[0145] Example 6

[0146] This embodiment is basically the same as Example 4, except that step S3 is different; the remaining steps and parameters are the same as in Example 4. Specifically, step S3 in this embodiment includes the following steps:

[0147] The filler powder, water, pumping agent (purchased from Hongzhida, model 25kg / JC / 473-2001), foaming agent (purchased from Maclean, model CAS: 80-17-1), and cement were mixed in a mass ratio of 200:250:25:50:500. After thorough mixing, 5wt% of expanding agent was added, and the mixture was stirred again thoroughly. Once all components were fully combined, the mixture was placed in a mold and allowed to expand for 7 days. After curing, the mixture was crushed to obtain biomass filler with a particle size of 3cm~5cm.

[0148] Example 7

[0149] This example is essentially the same as Example 4, except that the mass ratio of biomass waste powder to Fe3O4 solution differs in S2. All other steps and parameters are identical to those in Example 4. Specifically, in this example, the mass ratio of biomass waste powder to Fe ions is 2:0.01.

[0150] Example 8

[0151] This example is essentially the same as Example 4, except that the mass ratio of biomass waste powder to Fe3O4 solution differs in S2. All other steps and parameters are identical to those in Example 4. Specifically, in this example, the mass ratio of biomass waste powder to Fe ions is 2:0.02.

[0152] Example 9

[0153] This example is essentially the same as Example 4, except that the mass ratio of biomass waste powder to Fe3O4 solution differs in S2. All other steps and parameters are identical to those in Example 4. Specifically, in this example, the mass ratio of biomass waste powder to Fe ions is 2:0.04.

[0154] Example 10

[0155] This example is essentially the same as Example 4, except that the mass ratio of biomass waste powder to Fe3O4 solution differs in S2. All other steps and parameters are identical to those in Example 4. Specifically, in this example, the mass ratio of biomass waste powder to Fe ions is 2:0.05.

[0156] Example 11

[0157] This example is essentially the same as Example 4, except that the type of metal solution in S2 is different. The remaining steps and parameters are the same as in Example 4. Specifically, in this example, MnO2 solution is used instead of Fe3O4 solution, and the mass ratio of biomass waste powder to Mn ions is 2:0.03.

[0158] Comparative Example 1

[0159] This comparative example is essentially the same as Example 1, except that step S2 is different; the remaining steps and parameters are consistent with Example 1. Specifically, step S2 in this comparative example includes the following steps:

[0160] Biomass waste powder was mixed with water to obtain a suspension; this suspension was then poured into a porcelain crucible and fired in a muffle furnace at 200°C for 4 hours. After removal and cooling, the filler powder was obtained. The volume ratio of biomass waste powder to water was 1:2.

[0161] Comparative Example 2

[0162] This example is essentially the same as Example 1, except that in S5 the constructed wetland system does not include the biomass filler layer 3. The remaining steps and parameters are identical to those in Example 1. Specifically, S5 in this comparative example includes the following steps:

[0163] Construct an artificial wetland system, which from bottom to top includes a 10cm thick sand and gravel layer 1, a 10cm thick first artificial gravel layer 2, and a 20cm thick second artificial gravel layer 4.

[0164] Some steps and parameters in Examples 1-11 and Comparative Examples 1-2 are shown in Table 1 below.

[0165] Table 1

[0166]

[0167] The effluent quality of the constructed wetlands constructed in the above embodiments and comparative examples was tested, and the results are shown in the table below. In the table, "Whether it meets the standard" refers to whether the effluent from the constructed wetlands meets the Class V surface water standard.

[0168] Table 2

[0169]

[0170] As shown in Tables 1-2, the only difference between Examples 4 and Examples 7-10 is the mass ratio of biomass waste powder to Fe3O4 solution. Within the range of 2:(0.01~0.03), as the mass of Fe3O4 solution increases, the COD, BOD, phosphorus content, and nitrogen content of the effluent all decrease. When the mass ratio of biomass waste powder to Fe3O4 solution exceeds 2:0.03, it is possible that with the increase of iron ion concentration, metal consolidation occurs inside the micropores of biomass waste, and the porosity and surface area decrease accordingly, weakening the removal effect of pollutants. As a result, the final constructed wetland has a slightly lower wastewater removal effect than when the mass ratio is 2:0.03.

[0171] In Comparative Example 1, no metal solution was used to dope the biomass waste powder, resulting in an constructed wetland system with a significantly lower wastewater treatment efficiency than those in Examples 1-11. The constructed wetland in Comparative Example 2 lacked a biomass packing layer 3, thus its wastewater treatment capacity was very limited.

[0172] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0173] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for preparing a biomass filler, characterized in that, Includes the following steps: A suspension was prepared by mixing biomass waste residue powder with a metal ion solution; The suspension is subjected to calcination to prepare filler powder; The biomass filler is prepared by mixing the filler powder with additives and then undergoing an expansion process.

2. The method for preparing biomass filler according to claim 1, characterized in that, The metal ions are derived from one or more of Fe3O4 and MnO2; Furthermore, the mass ratio of the biomass waste powder to the metal ions is 2:(0.01~0.05).

3. The method for preparing biomass filler according to claim 1, characterized in that, Before mixing the biomass waste powder with the metal ion solution, the method further includes the following step: ultrasonic treatment of the biomass waste powder; Optionally, the frequency of the ultrasonic treatment is 140kHz~160kHz, and the duration is 0.8h~1.2h; Optionally, after ultrasonic treatment, the method further includes the following step: drying the biomass waste powder; Further optionally, the drying temperature is 100℃~110℃.

4. The method for preparing biomass filler according to any one of claims 1 to 3, characterized in that, The preparation method of the biomass waste residue powder includes the following steps: sequentially crushing and grinding the biomass waste residue from the power plant to prepare the biomass waste residue powder; Optionally, after crushing and before grinding, the following steps are also included: acid leaching the crushed power plant biomass waste residue with an acid solution; Further optionally, the acid solution includes one or more of phosphoric acid solution, sulfuric acid solution and nitric acid solution; Further optionally, the mass ratio of the acid solution to the pulverized biomass waste residue from the power plant is (1.5~2.5):

1.

5. The method for preparing biomass filler according to any one of claims 1 to 3, characterized in that, The particle size of the biomass waste powder is less than or equal to 125 μm; and / or, The biomass filler has a particle size of 3cm to 5cm; and / or, The firing temperature is 180℃~220℃, and the time is 3h~5h.

6. The method for preparing biomass filler according to any one of claims 1 to 3, characterized in that, The additives include pumping agents, foaming agents, cement, and expanding agents; Optionally, the mass ratio of the filler powder, water, pumping agent, foaming agent and cement is (100~200):(240~260):(20~30):(45~55):(450~550). Optionally, the amount of the expanding agent added is 4wt% to 6wt%, based on the sum of the masses of the filler powder, the water, the pumping agent, the foaming agent and the cement.

7. The method for preparing biomass filler according to any one of claims 1 to 3, characterized in that, Methods for mixing biomass waste powder with metal ion solutions include stirring; Optionally, the stirring speed is 100 r / min to 260 r / min.

8. A biomass filler, characterized in that, It is prepared by the method of any one of claims 1 to 7.

9. An artificial wetland, characterized in that, It includes a sand and gravel layer, a first artificial gravel layer, a biomass filler layer, and a second artificial gravel layer, which are stacked in sequence. The biomass packing layer includes the biomass packing as described in claim 8.

10. The constructed wetland according to claim 9, characterized in that, The sand and gravel layer comprises sand and gravel with a particle size of 0.2 cm to 0.5 cm; and / or, The first artificial gravel layer comprises first artificial gravel with a particle size of 1 cm to 3 cm; and / or, The second artificial gravel layer includes second artificial gravel with a particle size of 1 cm to 3 cm; and / or, The thickness of the sand and gravel layer is 8cm to 12cm; and / or, The thickness of the first artificial gravel layer is 8cm to 12cm; and / or, The thickness of the biomass filler layer is 50cm~70cm; and / or, The thickness of the second artificial gravel layer is 18cm to 22cm.

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