Ecological floating island enhanced by coupling autotrophic microorganisms and application of ecological floating island

Abstract

The invention provides an autotrophic microorganism coupled enhanced ecological floating island and application thereof, and belongs to the technical field of water body ecological restoration and environmental protection. The ecological floating island comprises a supporting floating layer, a biological enhancement layer and a planting layer which are arranged from bottom to top, and the biological enhancement layer comprises a particle carrier bed, a zeolite-magnetic activated carbon particle carrier arranged in the particle carrier bed and an anaerobic ammonia oxidation biological membrane attached to the surface of the zeolite-magnetic activated carbon particle carrier in a membrane mode. The ecological floating island is mainly used for denitrification treatment of a water body, and through the arrangement of the biological enhancement layer, a microcirculation system for microorganism-plant synergistic denitrification and carbon sequestration is enhanced, the water quality purification effect of the ecological floating island is improved, and meanwhile, the greenhouse gas emission is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of water body ecological restoration and environmental protection, and in particular relates to an ecological floating island coupled with autotrophic microbial enhancement and application thereof. Background Art

[0002] Water pollution is caused by excessive pollutants in rivers or lakes, which causes an imbalance between water reoxygenation and oxygen consumption, and damages the self-purification function of the aquatic ecosystem. A large amount of pollutants such as nitrogen, phosphorus, and organic matter are deposited in the riverbed mud, which will also release high-concentration pollution into the water body through repeated exchanges with the overlying water body, becoming a persistent endogenous source of pollution, seriously affecting the long-term cleanliness of the water body. At the same time, the mud also contains harmful substances such as heavy metals, and will undergo anaerobic degradation, easily corrupt and produce foul odors, exacerbating the black and smelly water body and further pollution.

[0003] There are three main technologies and methods for ecological restoration of polluted urban water bodies: (1) Physical methods: artificial aeration, dredging of sediments, water distribution, etc., which have unstable effects and can only treat the symptoms but not the root cause; (2) Chemical methods: adding chemical agents, etc., which are prone to secondary pollution and are expensive; (3) Ecological methods: using appropriate plants to imitate the ecological communities in nature, and strengthening the self-purification capacity of the water body through plant communities to repair polluted water bodies. Ecological floating islands, also called artificial floating beds or ecological floating beds, are based on ecological principles. They use soilless cultivation technology to configure aquatic plants, utilize water space and nutritional niches, and build a highly natural ecosystem to eliminate river water pollution and purify water quality. This technology is not only conducive to increasing the total amount of greening and improving river water quality, but also can protect biodiversity, enrich river landscapes, and optimize the ecological environment.

[0004] Traditional ecological floating islands mainly remove nitrogen pollutants from water bodies based on the traditional nitrification-denitrification principle. The functional microorganisms in the nitrification process are mainly aerobic bacteria, which require sufficient aeration to complete the conversion of ammonia nitrogen into nitrite nitrogen and nitrate nitrogen, increasing the operating energy consumption; while the main functional microorganisms in the denitrification process are heterotrophic bacteria, which need carbon sources as electron donors to convert NO 2 - and NO 3 - Restore to N 2 In the process, organic matter will be decomposed into CO 2 Emissions to the atmosphere will also generate N 2 O emissions. The comprehensive environmental effect of ecological floating islands is not high. The role of microorganisms in traditional ecological floating islands is not fully exerted, and usually requires external energy such as aeration and oxygenation to improve the denitrification efficiency of the system. In addition, there are greenhouse gas emissions such as carbon dioxide and nitrous oxide, which are not conducive to alleviating the greenhouse effect. The comprehensive environmental effect of ecological floating islands needs to be improved.

[0005] Anaerobic ammonium oxidation is an energy-saving and consumption-reducing autotrophic denitrification technology. The functional microorganism anaerobic ammonium oxidizing bacteria can directly convert NH 4 + and NO 2 - Synchronous conversion to N 2 , no N is produced in the metabolic pathway 2 Compared with traditional nitrification-denitrification biological denitrification, it can reduce oxygen consumption by 62.5%, does not require a carbon source, and has low sludge production. It is the most energy-saving and efficient denitrification technology to date. However, there is little research on anaerobic ammonium oxidation technology in ecological floating islands.

[0006] CN208454628 discloses a composite ecological autotrophic denitrification sewage treatment device, which adds a traditional ecological floating island on the basis of the anaerobic ammonium oxidation process to solve the problem of low phosphorus removal effect of the anaerobic ammonium oxidation process. However, the anaerobic ammonium oxidizing bacteria in the device are mainly dispersed in the sewage and are not part of the ecological floating island, which leads to its use in artificial sewage treatment facilities and is difficult to be applied on a large scale in natural water bodies. Summary of the invention

[0007] In order to address the deficiencies of the prior art, the present invention provides an ecological floating island coupled with autotrophic microbial enhancement, which adds a biological enhancement layer with autotrophic anaerobic anaerobic ammonia-oxidizing bacteria as the core functional microorganisms, thereby enhancing the efficiency of the microbial-plant synergistic denitrification and carbon fixation microcirculation system, improving the water purification efficiency while not generating greenhouse gas emissions, thereby greatly improving the environmental benefits of the ecological floating island on the basis of ensuring ecological benefits.

[0008] The present invention proposes an ecological floating island coupled with autotrophic microbial enhancement, comprising a floating layer, a biological enhancement layer and a planting layer arranged from bottom to top, wherein the biological enhancement layer comprises a granular carrier bed, a zeolite-magnetic activated carbon granular carrier arranged inside the granular carrier bed, and an anaerobic ammonia oxidation biofilm attached to the surface of the zeolite-magnetic activated carbon granular carrier in the form of a film.

[0009] Furthermore, the filling rate of the zeolite-magnetic activated carbon particle carrier in the particle carrier bed is 40% to 70%.

[0010] Furthermore, in the zeolite-magnetic activated carbon particle carrier, the mass ratio of zeolite to magnetic activated carbon is (2-5):1; Preferably, the particle size of the zeolite-magnetic activated carbon particle carrier is 4-6 mm.

[0011] Furthermore, the zeolite-magnetic biochar particle carrier is prepared by the following steps: (1) Pre-grinded zeolite microparticles with a diameter of less than 2 mm and magnetic activated carbon powder are mixed in a mass ratio of 3:1 to form a zeolite-magnetic biochar mixed powder; (2) preparing the zeolite-magnetic biochar mixed powder into particles with a particle size of 4-6 mm; (3) Activate the above particles at 900-1100° C. for 1-3 hours to obtain a zeolite-magnetic biochar particle carrier.

[0012] Furthermore, the anaerobic ammonium oxidation biofilm is cultured in a fixed bed reactor, comprising the following steps: (1) filling a fixed bed reactor with a zeolite-magnetic biochar particle carrier; (2) Inoculating the fixed bed reactor with sludge containing anaerobic ammonium oxidizing bacteria at an inoculation concentration of 1000-3000 mg / L; (3) The operating conditions of the fixed bed reactor are as follows: the water inlet and outlet are bottom-in and top-out; the inlet COD is 80-130 mg / L, ammonia nitrogen is 10-20 mg / L, total nitrogen is 15-25 mg / L, and total phosphorus is 0.5-2.0 mg / L; the temperature is 15-25°C, and the hydraulic retention time is 0.5-3 days; (4) After the fixed bed reactor has been running for 20-60 days, an anaerobic ammonium oxidizing biofilm is attached and grown on the surface of the zeolite-magnetic biochar particle carrier.

[0013] Furthermore, the floating layer is composed of floating plates in modular form; Preferably, trapezoidal buckles are evenly arranged around the floating plate. Furthermore, the planting layer is composed of a coconut fiber carrier bed, a root fixer and aquatic plants, the root fixer is distributed in the coconut fiber carrier bed, and the aquatic plants are planted in the root fixer; Preferably, the root anchors are evenly embedded in the coconut fiber bed, with a placement density of 0.1 square meters per root anchor.

[0014] Furthermore, the floating plate and the particle carrier bed are connected by a hinge, and the particle carrier bed and the coconut fiber carrier bed are connected by iron wire.

[0015] The present invention also proposes the use of any of the above-mentioned ecological floating islands in water body denitrification treatment.

[0016] Furthermore, the water body includes at least one of a natural water body, an artificial landscape water body or secondary effluent from a sewage treatment plant; Preferably, the natural water bodies include rivers and lakes. The present invention has the following advantages: On the basis of the traditional ecological floating island, the present invention adds a biological reinforcement layer with autotrophic anaerobic ammonia nitrogen oxidizing bacteria as the core functional microorganisms, and in view of the actual conditions in the polluted water body, such as low pollution concentration and metal ion inhibition, which are not conducive to the efficient operation of anaerobic ammonia oxidizing bacteria, a zeolite-magnetic activated carbon particle carrier is set to quickly enrich low-concentration nitrogen pollutants in the polluted water body, create a microenvironment with high substrate concentration for anaerobic ammonia oxidizing bacteria, and at the same time adsorb and passivate metal pollutants in the water body to avoid their inhibition of the production of anaerobic ammonia oxidizing bacteria, thereby ensuring the stable and efficient operation of the core functional microorganisms. By setting up a biological reinforcement layer, the ecological floating island strengthens the efficiency of microorganism-plant synergistic denitrification and carbon fixation, improves the water purification effect of the ecological floating island, and effectively reduces greenhouse gas emissions. The ecological floating island has a compact structure, modular installation, energy saving and consumption reduction, environmental friendliness, convenient management, and easy implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 It is a structural schematic diagram of the ecological floating island in the implementation case of the present invention; Figure 2 This is a schematic diagram of the structure of the floating layer in an embodiment of the present invention; Figure 3 Schematic diagram of the structure of the bio-enhanced layer in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a particle carrier in an embodiment of the present invention; Figure 5 Schematic diagram of the structure of the planting layer in the embodiment of the present invention.

[0018] Description of reference numerals: Floating layer-1; floating plate-11; trapezoidal buckle-12; Bio-enhanced layer-2; zeolite-magnetic activated carbon granular carrier-21; granular carrier bed-22; anaerobic ammonium oxidation biofilm-211; zeolite-212; magnetic activated carbon-213; Planting layer-3; Coconut coir fiber carrier bed-31; Root fixer-32; Polluted water bodies - 4. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0020] The inventors of the present application have found that anaerobic ammonium oxidizing bacteria can 4 + and NO 2 - The affinity constant is high, and it is necessary to enrich the low concentration of ammonia nitrogen and nitrite nitrogen in the polluted water to achieve efficient denitrification. At the same time, a certain concentration of heavy metals in the water will inhibit the activity of anaerobic ammonium oxidizing bacteria, and it is necessary to avoid the inhibition of heavy metals on anaerobic ammonium oxidizing bacteria.

[0021] An embodiment of the present invention proposes an ecological floating island coupled with autotrophic microbial enhancement, including a floating layer 1, a biological enhancement layer 2 and a planting layer 3 arranged from bottom to top, wherein the biological enhancement layer 2 includes a granular carrier bed 22, a zeolite-magnetic activated carbon granular carrier 21 arranged inside the granular carrier bed 22, and an anaerobic ammonia oxidation biofilm 211 attached to the surface of the zeolite-magnetic activated carbon granular carrier in the form of a film.

[0022] The ecological floating island coupled with autotrophic microorganism enhancement proposed in the embodiment of the present invention is provided with a biological enhancement layer with autotrophic anaerobic anaerobic ammonia-oxidizing bacteria as the core functional microorganism, and a zeolite-magnetic activated carbon particle carrier 21 is provided. Zeolite can be used to quickly enrich low-concentration nitrogen pollutants in polluted water bodies, creating a microenvironment with a high substrate concentration for anaerobic ammonia-oxidizing bacteria. At the same time, the magnetic activated carbon particles can adsorb and passivate metal pollutants in the water body to avoid their inhibition of the production of anaerobic ammonia-oxidizing bacteria, while improving the water purification efficiency without generating greenhouse gas emissions. In addition, the ecological floating island can be used in natural water bodies (lakes, rivers, etc.) and can be recycled, so that the environmental benefits of the ecological floating island can be greatly improved on the basis of ensuring ecological benefits. The ecological floating island has a compact structure, modular installation, energy saving and consumption reduction, environmental friendliness, convenient management, and easy implementation.

[0023] In one embodiment of the present invention, the filling rate of the zeolite-magnetic activated carbon particle carrier 21 in the particle carrier bed 22 is 40% to 70%.

[0024] In a preferred embodiment of the present invention, the particle size of the zeolite-magnetic activated carbon particle carrier 21 is 4-6 mm.

[0025] In a preferred embodiment of the present invention, in the zeolite-magnetic activated carbon granular carrier 21, the mass ratio of zeolite 212 to magnetic activated carbon 213 is (2-5): 1. In the embodiment of the present invention, the zeolite in the granular carrier is used to enrich low concentrations of ammonia nitrogen and nitrite nitrogen in the water body, creating a microenvironment with a high substrate concentration for anaerobic ammonia oxidizing bacteria. The magnetic activated carbon in the granular carrier is used to adsorb and passivate heavy metals in polluted water bodies to prevent them from inhibiting anaerobic ammonia oxidizing bacteria.

[0026] In one embodiment of the present invention, the zeolite-magnetic biochar particle carrier is prepared by the following steps: (1) Pre-grinded zeolite microparticles with a diameter of less than 2 mm and magnetic activated carbon powder are mixed in a mass ratio of 3:1 to form a zeolite-magnetic biochar mixed powder; (2) preparing the zeolite-magnetic biochar mixed powder into particles with a particle size of 4-6 mm; (3) Activate the above particles at 900-1100° C. for 1-3 hours to obtain a zeolite-magnetic biochar particle carrier.

[0027] In the embodiment of the present invention, zeolite-magnetic biochar is provided to strengthen the microcirculation system of pollutants-microorganisms-aquatic plants, enrich low-concentration pollutants and adsorb and passivate metal pollutants, thereby improving the purification effect of the ecological floating island and effectively reducing greenhouse gas emissions. In a preferred embodiment of the present invention, the anaerobic ammonium oxidation biofilm is cultured in a fixed bed reactor, comprising the following steps: (1) filling a fixed bed reactor with a zeolite-magnetic biochar particle carrier; (2) Inoculating the fixed bed reactor with sludge containing anaerobic ammonium oxidizing bacteria at an inoculation concentration of 1000-3000 mg / L; (3) The operating conditions of the fixed bed reactor are as follows: the water inlet and outlet are bottom-in and top-out; the inlet COD is 80-130 mg / L, ammonia nitrogen is 10-20 mg / L, total nitrogen is 15-25 mg / L, and total phosphorus is 0.5-2.0 mg / L; the temperature is 15-25°C, and the hydraulic retention time is 0.5-3 days; (4) After the fixed bed reactor has been running for 20-60 days, an anaerobic ammonium oxidizing biofilm is attached and grown on the surface of the zeolite-magnetic biochar particle carrier.

[0028] Preferably, in the anaerobic ammonium oxidation biofilm, the anaerobic ammonium oxidation activity is 15-45 mg / (gVSS·d).

[0029] More preferably, the source of anaerobic ammonium oxidizing bacteria: the anaerobic ammonium oxidizing bacteria are derived from a laboratory-scale expanded sequencing batch reactor (SBR) (100 L), the influent of which is domestic sewage, and it has been operating stably for more than 300 days, and the anaerobic ammonium oxidizing bacteria are mainly Candidatus Kuenenia and Candidatus Brocadia.

[0030] In the embodiment of the present invention, anaerobic ammonia oxidizing bacteria are attached to the surface of the zeolite-magnetic activated carbon particle carrier in the form of a biofilm, and the nitrogen pollution enriched in the particle carrier is directly converted into nitrogen gas without the need for additional oxygenation or additional organic matter, thereby achieving water denitrification and improving the removal efficiency of nitrogen pollutants. At the same time, carbon dioxide and nitrous oxide are not emitted, effectively avoiding greenhouse gas emissions.

[0031] In one embodiment of the present invention, the floating layer 1 is modularly composed of floating plates 11. The floating layer 1 is used to support the bio-enhancement layer 2 and the planting layer 3, so that they float on the water surface for a long time. Preferably, the floating plates are polyethylene floating plates. Preferably, trapezoidal buckles 12 are evenly arranged around the floating plate 11. The arrangement of the trapezoidal buckles 12 is mainly to facilitate modular assembly. Preferably, the trapezoidal buckles 12 are arranged on the floating plate 11 at intervals according to the hollow arrangement on the floating plate 11 and the protrusion arrangement on the floating plate 11.

[0032] In one embodiment of the present invention, the planting layer 3 is composed of a coconut palm fiber carrier bed 31, a root fixer 32 and aquatic plants, wherein the root fixer 32 is distributed in the coconut palm fiber carrier bed 31, and the aquatic plants are planted in the root fixer 32. In the embodiment of the present invention, the root fixer serves as a carrier of the aquatic plants, and the aquatic plants are vertically planted in the root fixer, and their roots extend through the coconut palm fibers to the bio-enhancement layer to directly absorb nutrients in the water body. Preferably, the aquatic plants are cold-resistant and have strong carbon fixation capabilities.

[0033] In one embodiment of the present invention, the root anchors 32 are evenly embedded in the coconut fiber bed 31, and the placement density is 0.1 square meters per root anchor.

[0034] In a preferred embodiment of the present invention, the floating plate 11 and the particle carrier bed 22 are connected by a hinge, and the particle carrier bed 22 and the coconut fiber carrier bed 31 are connected by iron wires, so that the floating plate 11 and the particle carrier bed 22 can be flexibly disassembled and assembled.

[0035] The embodiment of the present invention also proposes the application of any of the above ecological floating islands in water denitrification treatment.

[0036] Preferably, the water body includes at least one of a natural water body, an artificial landscape water body or secondary effluent from a sewage treatment plant. More preferably, the natural water body includes a river or a lake.

[0037] The present invention will be described in detail below with reference to embodiments.

[0038] Example 1 An ecological floating island coupled with autotrophic microbial enhancement It consists of a floating layer 1, a biological enhancement layer 2 and a planting layer 3 arranged from bottom to top.

[0039] The floating layer 1 is a whole polyethylene floating plate 11, which is 1 meter long, 0.5 meter wide and 0.08 centimeters thick. The trapezoidal buckle 12 passes through the floating plate 11, and the lengths of the upper and lower bottom sides thereof are 0.1 meter and 0.05 meter respectively, and the height is 0.08 meter. The biological enhancement layer 2 includes a particle carrier bed 22, a zeolite-magnetic activated carbon particle carrier 21 disposed inside the particle carrier bed 22, and an anaerobic ammonia oxidation biofilm 211 attached to the surface of the zeolite-magnetic activated carbon particle carrier in the form of a film; The particle carrier bed 22 is an open polyethylene box with a length, width and height of 1 meter, 0.5 meter and 0.1 meter respectively, and an effective volume of the box is 40L; the bottom of the particle carrier bed 22 is evenly distributed with perforations with a diameter of 3-5 mm to facilitate water circulation and flow; The particle size of the zeolite-magnetic activated carbon particle carrier 21 is 4-6 mm. In the zeolite-magnetic activated carbon particle carrier 21, the mass ratio of zeolite 212 to magnetic activated carbon 213 is 3:1. The zeolite-magnetic biochar particle carrier is prepared by the following steps: (1) Pre-grinded zeolite microparticles with a diameter of less than 2 mm and magnetic activated carbon powder are mixed in a mass ratio of 3:1 to form a zeolite-magnetic biochar mixed powder; (2) preparing zeolite-magnetic biochar mixed powder into particles with a particle size of 5 mm; (3) activating the above particles at 1000° C. for 2 hours to obtain a zeolite-magnetic biochar particle carrier; The anaerobic ammonium oxidation biofilm is cultured in a fixed bed reactor, comprising the following steps: (1) Filling the fixed bed reactor with zeolite-magnetic biochar particle carrier with a filling rate of 60%; (2) inoculating the above-mentioned sludge containing anaerobic ammonium oxidizing bacteria into a fixed bed reactor at an inoculation concentration of 2000 mg / L; (3) The operating conditions of the fixed bed reactor are as follows: the water inlet and outlet are bottom-in and top-out; the inlet COD is 80-130 mg / L, ammonia nitrogen is 10-20 mg / L, total nitrogen is 15-25 mg / L, and total phosphorus is 0.5-2.0 mg / L; the temperature is 15-25°C, and the hydraulic retention time is 0.5 days; (4) After the fixed-bed reactor was operated for 30 days, an anaerobic ammonium oxidation biofilm was attached and grown on the surface of the zeolite-magnetic biochar particle carrier, and the anaerobic ammonium oxidation activity was 15-45 mg / (gVSS·d); Source of anaerobic ammonium oxidizing bacteria: The anaerobic ammonium oxidizing bacteria were derived from a laboratory-scale expanded sequencing batch reactor (SBR) (100 L). The reactor was fed with domestic sewage and operated stably for more than 300 days. The main anaerobic ammonium oxidizing bacteria were Candidatus Kuenenia and Candidatus Brocadia.

[0040] The planting layer 3 is composed of a coconut palm fiber carrier bed 31, a root fixer 32 and aquatic plants. The root fixer 32 is distributed in the coconut palm fiber carrier bed 31, and the aquatic plants are planted in the root fixer 32; the length, width and height of the coconut palm fiber carrier bed 31 are 1 meter, 0.5 meter and 0.1 meter respectively; the preparation method of the coconut palm fiber carrier bed 31 is that the coconut palm fibers 31 are cleaned and combed neatly to make a coconut palm fiber carrier bed as a carrier for plant growth; the root fixers 32 are evenly embedded in the coconut palm fiber bed body 31, and the placement density is 0.1 square meters per piece.

[0041] The floating plate 11 and the particle carrier bed 22 are connected by a hinge, and the particle carrier bed 22 and the coconut fiber carrier bed 31 are connected by iron wires.

[0042] Comparative Example 1 Same as Example 1, except that no biological reinforcement layer is provided.

[0043] Comparative Example 2 The same as Example 1, except that the bio-augmentation layer is inoculated with traditional nitrification-denitrification denitrification bacteria to replace the autotrophic anaerobic ammonia oxidizing bacteria.

[0044] Comparative Example 3 Same as Example 1, except that ceramsite is used to replace the zeolite-magnetic activated carbon particle carrier.

[0045] Test Example 1 Water purification effect of ecological floating island The ecological blankets obtained in Example 1 and Comparative Examples 1-3 were subjected to simulated sewage treatment; The irises cultivated in the experiment are evenly planted in the root fixer 32, and the roots of the irises are located below the water surface, directly absorbing nutrients in the water body.

[0046] The prepared ecological floating island was placed in a water tank with a length, width and height of 1.2m, 0.6m and 0.8m respectively; the effective volume of the water tank was 500L; 300L of simulated sewage was added to the water tank, and the main water quality indicators of the sewage were as shown in Table 1: COD 120 mg / L, ammonia nitrogen 15 mg / L, total nitrogen 20 mg / L, total phosphorus 1 mg / L, iron 5mg / L, chromium 4mg / L, hydraulic retention time 3 days, temperature at room temperature, no aeration. After 60 days of operation, the removal rate of pollutants in the water was determined, and the results are shown in Table 1.

[0047] Table 1 Water purification effect of ecological floating island

[0048] As shown in Table 1, the ecological blanket for water restoration obtained in Example 1 of the present invention not only has a strong ability to remove nitrogen, phosphorus and COD in polluted water, but also has a high removal rate for metal pollutants. After 60 days of stable operation, it can ensure that the COD removal rate reaches 65%, the ammonia nitrogen removal rate reaches 75%, and the TP removal rate reaches 73%, and the urban water body is free of black and odor standards, and the dissolved oxygen DO> 2 mg / L. At the same time, it has the characteristics of flexible construction, low construction cost, simple process, and low maintenance and management cost after construction.

[0049] By comparing Comparative Example 1 and Example 1, it can be seen that the removal rates of various water quality indicators in Example 1 are significantly higher than those in Example 1, indicating that the provision of a biological enhancement layer effectively improves the overall purification efficiency of the ecological floating island.

[0050] By comparing Comparative Example 2 and Example 1, it can be seen that the removal rates of various water quality indicators in Example 1 are higher than those in Example 2, indicating that the sewage purification efficiency of the traditional nitrification-denitrification denitrification process is not as good as that of the anaerobic ammonia oxidation process without aeration. In particular, the effluent DO increased significantly in Example 1, while it decreased in Comparative Example 2. This is mainly because the functional microorganisms in Example 1 are heterotrophic bacteria, which consume dissolved oxygen in the denitrification process and decompose organic matter into carbon dioxide and discharge it into the atmosphere. However, since the experimental device is not aerated, the nitrification and denitrification process also consumes a part of the dissolved oxygen. The lower dissolved oxygen limits the decomposition of organic matter by heterotrophic bacteria, and the COD removal rate in Example 2 is not high.

[0051] By comparing Comparative Example 3 with Example 1, it can be seen that the main indicators of Comparative Example 3 are also lower than those of Example 1, indicating that zeolite-magnetic biochar has a significant promoting effect on the efficient denitrification of anaerobic ammonia oxidizing bacteria. This is mainly because the zeolite-magnetic activated carbon particle carrier can quickly enrich low-concentration nitrogen pollutants in polluted water, create a microenvironment with high substrate concentration for anaerobic ammonia oxidizing bacteria, and at the same time adsorb and passivate metal pollutants in the water to avoid their inhibition of the production of anaerobic ammonia oxidizing bacteria.

[0052] From the above comparative experimental results, it can be seen that the biological enhancement layer in this implementation case is used to strengthen the microcirculation system of pollutants-microorganisms-aquatic plants, achieving efficient removal of pollutants and effectively avoiding greenhouse gas emissions. In particular, the biological enhancement layer is set to autotrophic anaerobic anaerobic ammonia-oxidizing bacteria, and zeolite-magnetic activated carbon is set to promote the efficiency of anaerobic ammonia-oxidizing bacteria, further enhancing the denitrification and carbon fixation efficiency of microorganisms-aquatic plants, improving the water purification effect of the ecological floating island, saving aeration energy consumption, and effectively reducing greenhouse gas emissions.

Claims

1. An ecological floating island coupled with autotrophic microbial enhancement, characterized in that: It includes a floating layer, a biological enhancement layer and a planting layer arranged from bottom to top, wherein the biological enhancement layer includes a granular carrier bed, a zeolite-magnetic activated carbon granular carrier arranged inside the granular carrier bed, and an anaerobic ammonia oxidation biofilm attached to the surface of the zeolite-magnetic activated carbon granular carrier in the form of a film.

2. The ecological floating island according to claim 1, characterized in that: The filling rate of the zeolite-magnetic activated carbon particle carrier in the particle carrier bed is 40% to 70%.

3. The ecological floating island according to claim 1, characterized in that: In the zeolite-magnetic activated carbon particle carrier, the mass ratio of zeolite to magnetic activated carbon is (2-5):1; Preferably, the particle size of the zeolite-magnetic activated carbon particle carrier is 4-6 mm.

4. The ecological floating island according to any one of claims 1 to 3, characterized in that: The zeolite-magnetic biochar particle carrier is prepared by the following steps: (1) Pre-grinded zeolite microparticles with a diameter of less than 2 mm and magnetic activated carbon powder are mixed in a mass ratio of 3:1 to form a zeolite-magnetic biochar mixed powder; (2) preparing the zeolite-magnetic biochar mixed powder into particles with a particle size of 4-6 mm; (3) Activate the above particles at 900-1100° C. for 1-3 hours to obtain a zeolite-magnetic biochar particle carrier.

5. The ecological floating island according to claim 1, characterized in that: The anaerobic ammonium oxidation biofilm is cultured in a fixed bed reactor, comprising the following steps: (1) filling a fixed bed reactor with a zeolite-magnetic biochar particle carrier; (2) Inoculating the fixed bed reactor with sludge containing anaerobic ammonium oxidizing bacteria at an inoculation concentration of 1000-3000 mg / L; (3) The operating conditions of the fixed bed reactor are as follows: the water inlet and outlet are bottom-in and top-out; the inlet COD is 80-130 mg / L, ammonia nitrogen is 10-20 mg / L, total nitrogen is 15-25 mg / L, and total phosphorus is 0.5-2.0 mg / L; the temperature is 15-25°C, and the hydraulic retention time is 0.5-3 days; (4) After the fixed bed reactor has been running for 20-60 days, an anaerobic ammonium oxidizing biofilm is attached and grown on the surface of the zeolite-magnetic biochar particle carrier.

6. The ecological floating island according to claim 1, characterized in that: The floating layer is modularly composed of floating plates; Preferably, trapezoidal buckles are evenly arranged around the floating plate.

7. The ecological floating island according to claim 1, characterized in that: The planting layer is composed of a coconut palm fiber carrier bed, a root fixer and aquatic plants, wherein the root fixer is distributed in the coconut palm fiber carrier bed, and the aquatic plants are planted in the root fixer; Preferably, the root anchors are evenly embedded in the coconut fiber bed, with a placement density of 0.1 square meters per root anchor.

8. The ecological floating island according to claim 1, characterized in that: The floating plate and the particle carrier bed are connected by hinges, and the particle carrier bed and the coconut palm fiber carrier bed are connected by iron wires.

9. Use of the ecological floating island described in any one of claims 1 to 8 in denitrification treatment of water bodies.

10. The use according to claim 1, characterized in that: The water body includes at least one of a natural water body, an artificial landscape water body or secondary effluent from a sewage treatment plant; Preferably, the natural water bodies include rivers and lakes.

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