Artificial fish reef based on biomass bottom residue

Abstract

The application provides a kind of artificial reef based on biomass bottom residue, including the bottom plate of adsorption brick and water treatment structure on the bottom plate;The water treatment structure includes a central axis and adsorption brick on the central axis;The preparation raw material of the adsorption brick includes biomass bottom residue, cement;The central axis is inserted into the bottom plate.For the problems of prior art wetland ecological restoration and biomass bottom residue resource utilization, the purpose of the application is to provide a kind of artificial reef, which solves the problem of biomass bottom residue resource utilization, and is beneficial to wetland ecological restoration.

Description

Technical Field

[0001] This invention relates to the fields of biomass bottom residue resource utilization and wetland ecological restoration, and specifically to an artificial reef based on biomass bottom residue. Background Technology

[0002] Biomass bottom ash is the ash residue produced by burning biomass fuels such as straw and wood in biomass power plants, and it is currently the main waste generated during the power generation process of biomass power plants in my country. Biomass bottom ash lacks effective utilization methods and a market. In most cases, it is generally used for primary treatment such as landfilling, or simply dumped. This extensive treatment method not only lacks efficiency and occupies land resources, but also disrupts the ecological chain of nutrients essential for plant growth, hinders the development of biomass power generation, and increasingly becomes an economic and environmental burden. The treatment of biomass bottom ash is an urgent problem to be solved, and its rational utilization is of great significance for the sustainable development of direct biomass combustion.

[0003] The substrate used in constructed wetlands is also known as filter media or matrix. Wetland substrates not only provide a growth medium for plants and microorganisms but also directly remove pollutants through sedimentation, filtration, and adsorption. Traditional constructed wetlands use granular fillers such as gravel, ceramsite, zeolite, and fly ash, which have limited specific surface area and high porosity, making it difficult for microorganisms to attach and thus affecting the biochemical processes of wastewater treatment. While fillers such as soil and sand have a large specific surface area, their low porosity easily leads to matrix clogging. Therefore, neither is an ideal wetland substrate for wetland ecological restoration.

[0004] The inventors previously used biomass bottom residue as raw material to prepare biomass bottom residue bricks by combining biomass bottom residue of different particle sizes with cement. This addresses the problem of low utilization rate of ash residue from biomass power plants, leading to resource waste and environmental pollution. It provides a feasible resource utilization pathway for biomass bottom residue from power plants. Furthermore, this biomass bottom residue brick is prepared using a non-sintering technology, offering advantages such as no sintering, no high temperature and pressure, short processing cycle, and good treatment effect. It meets the GB 5085.3-2007 standard, exhibits extremely low heavy metal leaching, contains no harmful elements, poses no ecological risk, and is an environmentally friendly product. However, although the biomass bottom residue brick has high compressive strength, its effectiveness in wetland remediation is poor. The inventors also designed a clamp-type packing material using biomass bottom residue, but it must be placed along the water flow direction to form a water treatment packing system, creating a cross-flow effect to enhance water purification.

[0005] Currently, there are few technical solutions for wetland remediation using biomass bottom residue. Existing water treatment methods or biomass bottom residue utilization technologies have poor wetland remediation effects and are difficult to apply in practice. Summary of the Invention

[0006] To address the aforementioned issues of wetland ecological restoration and the resource utilization of biomass bottom residue, the present invention aims to provide an artificial reef. This artificial reef solves the problem of biomass bottom residue resource utilization and is beneficial for wetland ecological restoration. Artificial reefs are man-made structures placed in the sea to improve the marine ecological environment, create a favorable habitat for marine life, and provide places for fish and other organisms to reproduce, grow, forage, and seek shelter from predators, thereby achieving the goals of protection, propagation, and increased fish catches. This invention is the first to apply it to wetland ecological restoration with very good results.

[0007] The technical solution adopted by this invention to solve its technical problem is: An artificial reef based on biomass bottom residue includes a base plate composed of adsorption bricks and a water treatment structure located on the base plate; the water treatment structure includes a central shaft and adsorption bricks located on the central shaft; the central shaft is inserted into the base plate.

[0008] In this invention, the raw materials for preparing the adsorption brick include biomass bottom residue and cement; preferably, the raw materials for preparing the adsorption brick also include a water-soluble polymer. In this invention, the biomass bottom residue and cement are mixed and then solidified to obtain the adsorption brick; or the biomass bottom residue, cement, and water-absorbing polymer are mixed and then solidified to obtain the adsorption brick. Preferably, the water-absorbing polymer is solid polyethylene glycol, such as PEG2000, PEG6000, PEG8000, etc.

[0009] The above-mentioned method for preparing artificial reefs based on biomass bottom residue includes the following steps: (1) The adsorption brick is obtained by mixing biomass bottom residue and cement and then solidifying it; or the adsorption brick is obtained by mixing biomass bottom residue, cement and water-absorbing polymer and then solidifying it. (2) The base plate is composed of adsorption bricks; (3) Install the central shaft on the base plate, and then put the adsorption brick on the central shaft to obtain an artificial reef based on biomass bottom residue.

[0010] This invention discloses the application of an adsorption brick in the preparation of the aforementioned biomass-based artificial reefs, wherein the raw materials for preparing the adsorption brick include biomass residue and cement; or the raw materials for preparing the adsorption brick include biomass residue, cement, and a water-soluble polymer. The invention also discloses the application of the aforementioned biomass-based artificial reefs in wetland ecosystem restoration.

[0011] This invention discloses a method for restoring wetland ecology using the above-mentioned artificial reef based on biomass bottom residue, comprising the following steps: sinking the artificial reef based on biomass bottom residue into the wetland to restore the wetland ecology.

[0012] In this invention, the particle size of the biomass bottom residue is 0.5–20 mm, preferably 1–10 mm; the mass ratio of biomass bottom residue to cement is 10:(1–5); or the mass ratio of biomass bottom residue, cement, and water-soluble polymer is 10:(1–5):(0.5–2). Preferably, the mass ratio of biomass bottom residue to cement is 10:(2–3); or the mass ratio of biomass bottom residue, cement, and water-soluble polymer is 10:(2–3):(0.8–1.5).

[0013] In this invention, the cross-section of the adsorption brick is a 'well' structure, with a groove on each side, i.e., an opening in the middle of each side of the 'well' structure, and a column hole in the middle; the central axis passes through the column hole; the adsorption bricks are arranged vertically on the central axis; the bottom plate is provided with a bottom mud layer and a submerged plant planting layer.

[0014] The artificial reef disclosed in this invention includes a base plate and a water treatment column; the base plate is composed of a plurality of horizontally spliced ​​adsorption bricks, the water treatment column is mainly composed of a plurality of adsorption bricks strung together on a central axis, and also includes some conventional fasteners.

[0015] In this invention, the adsorption brick has a prismatic structure with grooves on the edges of its upper and lower surfaces and a central column hole, forming a 'well' structure. The prismatic structure allows multiple filler bricks to be assembled within a limited space while maintaining relative stability in water. The grooves and column hole increase the specific surface area of ​​the biomass bottom residue, enhancing its adsorption capacity, and also provide more habitats for aquatic organisms. Four identical cross-shaped prisms, interconnected and integrally structured, surround the column hole to form the adsorption brick structure. In each cross-shaped prism, the upper surface in the middle is flat, and the upper surfaces of the four sides are inclined planes; that is, in the cross-shaped prism, the middle of the upper surface is a rectangular horizontal plane, and its four sides slope outwards and downwards to form four rectangular inclined planes.

[0016] In this invention, the bottom plate is provided with a bottom mud layer and a submerged plant planting layer, specifically, the bottom mud layer and the submerged plant planting layer are provided in the column holes of the adsorption brick. Submerged plants can not only increase dissolved oxygen in the water through photosynthesis, but also adsorb certain pollutants and suspended solids in the water, increase water transparency, and provide a place for plankton and other microorganisms to live and reproduce.

[0017] Compared with the prior art, the beneficial effects of the present invention are: In this invention, biomass bottom residue and cement are mixed and then solidified to obtain adsorption bricks; or biomass bottom residue, cement, and a water-absorbing polymer are mixed and then solidified to obtain adsorption bricks. Preferably, the water-absorbing polymer is solid polyethylene glycol. Wetland ecological restoration is a long-term project with extensive waterways, requiring artificial reefs to have a long-term continuous restoration capacity, with a service life of several years. This not only places demands on the stability of artificial reefs but also poses a challenge to the internal structure of adsorption bricks. As is common knowledge, during adsorption treatment, adsorbents accumulate over time, and the adsorption capacity gradually decreases until it disappears. Furthermore, the presence of mud at the bottom of wetlands, which is both a favorable environment for the growth of water treatment plants and microorganisms and a factor that reduces the performance of adsorption bricks, is also a contributing factor. To address this, this invention creatively incorporates a water-soluble solid polymer during the preparation of the adsorption bricks. In the initial stages of preparation and application, the polymer occupies space inside the adsorption brick. As time progresses, in water at relatively low temperatures, the polymer slowly dissolves, gradually forming new pores, thus maintaining the performance of the adsorption brick or slowing down the decline in performance. In particular, the technical solution and structure adopted in this invention can maintain the stability of the artificial reef after the polymer is dissolved, thus meeting the general requirements for wetland ecological restoration.

[0018] The main component of this artificial reef, the adsorption brick, is made from biomass bottom residue, which poses a threat to the ecological environment. Its high porosity, large specific surface area, and excellent adsorption properties are rationally applied to wetland ecological restoration. This alters the water flow around the artificial reef, creating upwelling that carries nutrients from the bottom to the surface, promoting the proliferation of plankton and providing food for fish and shrimp. The resulting back eddy current accelerates the mixing of upper and lower water layers, increasing dissolved oxygen and carrying nutrients from the bottom to the upper layers, thereby increasing the microbial biomass in the area and providing a culture medium for attached organisms. Ultimately, this improves the aquatic ecological environment and effectively solves a major problem in ecological restoration. Therefore, this artificial reef has high scalability. This invention employs a method of planting submerged plants in the column holes of the bottom biomass bottom residue filler bricks in the bottom module, giving the artificial reef ecological functions. The submerged plants not only increase dissolved oxygen through photosynthesis but also adsorb certain pollutants and suspended solids, increasing water transparency and providing a habitat for plankton and other microorganisms. Attached Figure Description

[0019] Figure 1 This is a top view of the adsorption brick.

[0020] Figure 2 This is a side view of the adsorption brick.

[0021] Figure 3 This is a schematic diagram of the structure of an artificial reef.

[0022] Figure 4 This is a top view of the base plate.

[0023] Figure 5 This is a side view of an artificial reef.

[0024] Figure 6 This is a schematic diagram of a water treatment structure.

[0025] The components are: 1. base plate; 2. water treatment structure; 3. adsorption brick; 31. groove; 32. square column hole; 41. adsorption brick; 42. galvanized steel pipe; 43. PE pipe; 44. limit nut. Detailed Implementation

[0026] The method for preparing artificial reefs based on biomass bottom residue disclosed in this invention comprises the following steps: (1) The adsorption brick is obtained by mixing biomass bottom residue and cement and then solidifying it; or the adsorption brick is obtained by mixing biomass bottom residue, cement and water-absorbing polymer and then solidifying it. (2) The base plate is composed of adsorption bricks; (3) Install the central shaft on the base plate, and then put the adsorption brick on the central shaft to obtain an artificial reef based on biomass bottom residue.

[0027] Preferably, in step (1), biomass bottom residue and cement are mixed, and then water-absorbing polymer is added. After mixing, the mixture is cured to obtain an adsorbent brick. Further, biomass bottom residue, cement and water are mixed for 10 to 15 minutes, and then water-absorbing polymer is added. After mixing, the mixture is cured to obtain an adsorbent brick. The amount of water used is 15 to 25% of the total mass of biomass bottom residue and cement. After conventional stirring and mixing, the product is a thick slurry. Polyethylene glycol is then added, and after stirring for 1 to 2 minutes, it is poured into a mold. After observing the molding, the brick is demolded and left for 10 to 15 days to obtain an adsorbent brick. When leaving the brick, water is sprinkled on the surface until the surface is damp.

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and preferred embodiments. The orientations involved in this invention refer to the positional relationships during actual use. The raw materials of this invention are existing products; biomass bottom residue is the ash residue produced by burning fuel in biomass power plants. The primary biomass bottom residue is screened to obtain biomass bottom residue with a particle size of 1-10 mm. After washing with water, it is weathered and dried under natural conditions to obtain cleaned biomass bottom residue, which is used in the embodiments. The specific preparation operations and performance tests involved in this invention are all conventional techniques, conducted at room temperature, and the water quality test results are average values ​​with very small differences.

[0029] In this invention, the central shaft is a conventional product that can be installed on the base plate and is suitable for stringing together adsorption bricks. As an example, the central shaft is a galvanized steel pipe that passes through the column holes of each adsorption brick, with its lower end inserted into the base plate. Both its upper and lower ends have fixing components to maintain stability. Furthermore, a PE pipe is provided below the adsorption bricks, fitted onto the central shaft, to support the adsorption bricks, reduce corrosion of the galvanized steel pipe by water, extend its service life, and ensure good stability. Preferably, in the water treatment structure, the number of adsorption bricks is 1 to 15, and the spacing between the adsorption bricks is 5 to 25 cm. More preferably, in the water treatment structure, the number of adsorption bricks is 3 to 10, and the spacing between the adsorption bricks is 5 to 15 cm.

[0030] In this invention, the base plate is rectangular, and the number of adsorption bricks constituting it is preferably 12, arranged in four rows and three columns, with the central axis fixedly connected to the four corners of the base plate. Artificial reefs with this structure are not only easy to deploy but also convenient to place during use, and can achieve good stability and uniform water purification effect.

[0031] The adsorption bricks have a prismatic structure with grooves on the upper and lower edges and columnar holes in the center, forming a 'well' structure. This increased surface area enhances the biofilm formation of microorganisms, further improving water treatment efficiency. The grooves and columnar holes facilitate water flow and reduce clogging by the substrate. The mold design utilizes conventional technology. The bottom module, constructed from horizontally assembled bottom biomass filler bricks, allows the artificial reef to completely flatten on the water's bottom after deployment, effectively preventing heavier sediment particles from rising. It also effectively adsorbs nitrogen and phosphorus from the water, increasing water transparency. Furthermore, this structure is less prone to swaying due to water flow, ensuring good stability and facilitating the attachment and growth of aquatic organisms.

[0032] Example 1

[0033] Mix 100 kg of biomass ash and 25 kg of PO 42.5 cement. Stir at 150 r / min for 5 minutes at room temperature. Then add 22 kg of tap water and stir at 80 r / min for 15 minutes to obtain a slurry. Pour the slurry into a mold, level it, observe the molding process, demold it, and let it stand for 12 days to obtain an absorbent brick. Sprinkle water on the surface until it is damp during the standing process.

[0034] Example 2

[0035] Mix 100 kg of biomass ash and 25 kg of PO 42.5 cement. At room temperature, use a mixer to stir at 150 r / min for 5 minutes. Then add 22 kg of tap water and stir at 80 r / min for 15 minutes. Then add 11 kg of PEG8000 while stirring and stir for another 90 seconds to obtain a slurry. Pour the slurry into a mold that has been left to stand, smooth it, observe the molding process, demold it, and let it stand for 12 days to obtain an absorbent brick. Sprinkle water on the surface until it is damp during the standing process.

[0036] Figure 1 This is a top view of the adsorption brick. Figure 2 This is a side view of the adsorption brick. The adsorption bricks in Examples 1 and 2 have the same structure, a 'well'-shaped prismatic structure. Each prism has a vertical groove 31 running through both the top and bottom edges and the center. A square column hole 32 is located in the center, surrounded by four identical cross-shaped prisms 33 connected to each other. The prismatic structure allows multiple packing bricks to be assembled within a limited space and maintains relative stability in water. The grooves 31 and column holes 32 increase the specific surface area of ​​the biomass bottom residue, enhancing its adsorption capacity, and also provide more habitat for aquatic organisms. Each adsorption brick is 25cm long, 19cm wide, and 8cm high. Its central post hole 32 is 7.5cm long and 5cm wide. The upper surface of each cross-shaped prism 33 has a rectangular horizontal surface in the middle, 5cm long and 4.5cm wide, with its four sides sloping outwards and downwards to form four rectangular inclined surfaces. The height of the rectangular horizontal surface in the middle of the upper surface of the cross-shaped prism is 8cm (the thickest part of the adsorption brick), and the lowest height of the outer inclined surface is 6.5cm (the thinnest part of the adsorption brick). This inclined surface design further increases the specific surface area of ​​the biomass bottom residue, resulting in better purification performance.

[0037] Example 3

[0038] Reference Figure 3 , Figure 4 The artificial reef has a base plate 1 and four water treatment structures 2. The base plate is made of twelve adsorption bricks 3 horizontally bonded together. The bonding method is conventional technology, such as cement mortar bonding (in this embodiment), tile adhesive bonding, physical fixation, etc., and forms a grid-like rectangle with four rows and three columns. Reference Figure 5Each water treatment structure has an overall height of 160cm and consists of eight adsorption bricks 41, one galvanized steel pipe 42, and multiple PE pipes 43. The galvanized steel pipe passes through the central column hole of each brick and is connected vertically in sequence. Below the adsorption brick, the galvanized steel pipe is also fitted with an outer PE pipe with a diameter larger than the width of the column hole, forming an 8cm interval. Each biological purification column has a limiting nut 44 at the top and bottom to limit the vertical displacement of each brick. The upper and lower limiting nuts are fixed to the steel pipe by threaded engagement. In actual production, conventional methods such as clamps can also be used. The lower ends of the galvanized steel pipes of the four biological purification columns are fixedly connected to the four corners of the base plate (the column holes of the four corner adsorption bricks). The connection method can be grouting with sleeves. Artificial reefs with this structure are not only easy to deploy but also easy to place during use, and can achieve good stability and uniform water purification effect.

[0039] Example 4

[0040] Based on Example 3, the column holes 32 of the adsorption brick are provided with a bottom mud layer and a surface submerged plant planting layer. Submerged plants can not only increase dissolved oxygen in the water through photosynthesis, but also adsorb certain pollutants and suspended solids in the water, increase water transparency, and provide a place for plankton and other microorganisms to live and reproduce.

[0041] Example 5

[0042] The method of using artificial reefs is as follows: Artificial reefs are placed in wetland waters, which can alter the aquatic ecosystem, accelerate water mixing, prevent bottom sediment particles from rising to the surface, and increase water transparency. The biomass functional filler can also adsorb nutrients such as nitrogen and phosphorus from the water, and the submerged plants planted at the bottom can increase dissolved oxygen through photosynthesis, providing a habitat for microorganisms and plankton in the water. Therefore, this artificial reef solves the problem of biomass bottom sediment resource utilization and is beneficial to wetland ecological restoration.

[0043] According to tests, before the artificial reef was deployed, the water quality was classified as worse than Class V, with BOD: 12.3 mg / L, total nitrogen: 2.01 mg / L, total phosphorus: 0.42 mg / L, and hydraulic loading: 0.7 m³·m. -2 ·d -1 .

[0044] The artificial reefs of Example 4 were placed into the wetland water, with the adsorption bricks being those of Example 1 or Example 2. After 30 days of placement, the water quality was tested and found to be at or above Class IV of the Surface Water Environmental Quality Standard (GB3838-2002) (taking Example 2 as an example, BOD 5.5 mg / L, total nitrogen 1.02 mg / L, and total phosphorus 0.23 mg / L). This level remained above Class IV for six months.

[0045] Performance testing. The adsorbent bricks of Example 2 were immersed in 70°C water for one month, then removed and dried. The compressive strength before and after immersion was tested, showing a decrease of 2.7% and a decrease in weight, indicating that the polymer dissolved and the bricks still met the requirements for on-site construction.

[0046] Comparative test. A 60℃ aqueous solution containing 0.5 mg / L total phosphorus and 2.0 mg / L total nitrogen was divided into two portions, one for Example 1 and one for Example 2, respectively. After 50 days, the total phosphorus concentration in Example 1 was 0.209 mg / L and the total nitrogen concentration was 0.997 mg / L, while in Example 2 it was 0.194 mg / L and the total nitrogen concentration was 0.906 mg / L. This indicates that the dissolution of PEG increases pore size, which is beneficial for adsorption, thus enabling the artificial reef to maintain water quality at or above Class IV during long-term use.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An artificial reef based on biomass bottom residue, characterized in that: The device includes a base plate composed of adsorption bricks and a water treatment structure located on the base plate; the water treatment structure includes a central shaft and adsorption bricks located on the central shaft; the raw materials for preparing the adsorption bricks include biomass bottom residue, cement, and PEG8000; the central shaft is inserted into the base plate; the particle size of the biomass bottom residue is 0.5-20mm; the mass ratio of biomass bottom residue, cement, and PEG8000 is 10:(2-3):(0.8-1.5); the cross-section of the adsorption bricks is a 'well' structure, with grooves on each side and a column hole in the middle; the central shaft passes through the column hole; the adsorption bricks are arranged vertically on the central shaft; the base plate is provided with a bottom mud layer and a submerged plant planting layer.

2. The method for preparing artificial reefs based on biomass bottom residue as described in claim 1, characterized in that, Includes the following steps: (1) Mix biomass bottom residue and PO 42.5 cement, stir with a mixer at room temperature, add water, stir again, then add PEG8000 while stirring, and stir again to obtain slurry; then pour the slurry into a stationary mold, scrape it flat, observe the molding and demold, place it to obtain adsorbent brick, and sprinkle water on the surface until the surface is moist when placing it. (2) The base plate is composed of adsorption bricks; (3) Install the central shaft on the base plate, and then put the adsorption brick on the central shaft to obtain an artificial reef based on biomass bottom residue.

3. The method for restoring wetland ecology using artificial reefs based on biomass bottom residue as described in claim 1, characterized in that, Includes the following steps: The artificial reefs based on biomass bottom residue are sunk into the wetlands to restore the wetland ecosystem.

4. The application of the artificial reef based on biomass bottom residue as described in claim 1 in the restoration of wetland ecosystems.

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