A method for screening artificial reefs based on environmental impact

Abstract

The present invention belongs to the technical field of life cycle assessment, and relates to a method for screening artificial reefs based on environmental impact. The life cycle assessment method is used to conduct an environmental impact assessment on the production of four artificial reefs made of different materials, including two common materials: reinforced concrete and steel, and two production waste resource utilization materials: shell powder replacing 20% ​​of fine aggregate to make concrete, and steel slag replacing 20% ​​of cement to make concrete. First, the life cycle boundaries of the four materials of reefs are determined; then, the raw materials, resources, energy consumption of the different reef production processes and the consumption of the two waste pretreatment processes are collected; then, GaBi software is used to build a model, and CML2001 is used for characterization and normalization analysis. The present invention compares the energy consumption and environmental impact of the four materials in their life cycles from a full life cycle perspective, identifies the consumption of the two waste pretreatment processes, judges the environmental friendliness of the four materials, and proposes corresponding improvement measures.

Description

Technical Field

[0001] The invention belongs to the technical field of life cycle assessment and relates to an artificial fish reef screening method based on environmental impact. Background Art

[0002] The construction of marine ranches can improve marine environmental quality, provide habitats for fish, increase the abundance of biological resources, and promote sustainable aquaculture. The deployment of artificial reefs is a key component of marine ranch construction. Materials used to construct these reefs include concrete, steel, plastic, used ships and tires, and natural stone. With the development of marine fisheries, the choice of artificial reefs has shifted towards shell reefs and green concrete reefs. Research on artificial reef materials is also actively moving towards new materials such as industrial waste and biomaterials. However, this research has primarily focused on the structure and properties of these materials, while ignoring the energy consumption and environmental emissions of the various production stages. Furthermore, industrial waste, due to its complex composition, requires varying degrees of pretreatment before use as artificial reef material. Some LCA analyses of industrial waste and biomaterials have directly overlooked this pretreatment step, overestimating the environmental friendliness of waste resource utilization. Therefore, a method is needed to quantify the lifecycle environmental impacts of artificial reefs made of different materials. Summary of the Invention

[0003] In order to solve the above problems, the present invention proposes an artificial reef screening method based on environmental impact.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A method for screening artificial reefs based on environmental impacts comprises the following steps:

[0006] (1) Determination of objectives and scope: Considering factors such as scope of use, performance, and fish attracting effect, four types of artificial reef materials were selected, including two common materials: reinforced concrete and steel, and two production waste resource utilization materials: shell powder replacing 20% ​​of fine aggregate to make concrete, and steel slag replacing 20% ​​of cement to make concrete. Since the raw materials for making different artificial reefs are numerous and their sources are complex, the raw material transportation stage is not considered. The input and output of materials within the system boundary include: energy production and use, raw material production (pretreatment) and use, and pollutant emissions during the production stage. The functional unit is defined as the production of 10,000 individual reefs, a cubic frame reef with a size of 2m×2m×2m. The resource consumption and environmental emissions of the four artificial reef production processes are calculated separately.

[0007] (2) Inventory analysis: The raw materials, resources, energy consumption and waste gas emission data for the production of four artificial reefs and the consumption data for the two production waste pretreatment processes were obtained from the enterprise feasibility study report, environmental impact assessment report and published relevant references; the upstream traceability data for the energy and raw material production process were obtained from the professional database built into the life cycle assessment analysis tool GaBi software.

[0008] (3) Impact Assessment Method: Based on inventory data, GaBi software and the GaBi Database were used for modeling and calculation. Four artificial reef production models were established: cold-formed steel frame reef, reinforced concrete reef, concrete reef with shell powder replacing 20% ​​of fine aggregate, and concrete reef with steel slag replacing 20% ​​of cement. The pretreatment processes of shell and steel slag were incorporated into the model through upstream raw material tracing. The CML2001-Jan.2016 evaluation method was used for normalized calculations. Energy input, pollution output, and ecological damage were the main research contents. Based on the life cycle inventory of the four artificial reef materials, a characterization and normalization analysis was conducted. The environmental impact potential of each type of indicator was calculated, and the environmental impact of the production of different reef materials was identified and quantitatively assessed.

[0009] (4) Result analysis: Evaluate the results of the impact assessment, compare the energy consumption and environmental impact of the four materials during their life cycles, identify the consumption of the pretreatment process of the two waste materials (shell powder and steel slag), judge the environmental friendliness of the four materials and propose corresponding improvement measures.

[0010] Beneficial effects of the present invention:

[0011] This study quantifies the energy consumption and environmental impact potential of four major artificial reefs, including two reefs that utilize production waste, over their entire lifecycles. It analyzes which material, while achieving the same effect, consumes less energy and has the least environmental impact. It further clarifies the energy-saving and emission-reduction benefits of waste resource utilization, providing a reference for selecting artificial reefs in marine ranching. This study compares the energy consumption and environmental impact of the four materials over their entire lifecycles, identifies the consumption during the pretreatment process of the two waste materials, determines the environmental friendliness of the four materials, and proposes corresponding improvement measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the process flow chart for the production of cold-formed steel fish reefs.

[0013] Figure 2 This is the process flow chart for reinforced concrete fish reef production.

[0014] Figure 3 This is the process flow chart for shell pretreatment.

[0015] Figure 4This is the process flow chart of hot stuffing method for steel slag pretreatment. Specific implementation plan

[0016] The specific implementation of the present invention is further explained in conjunction with the technical solution and the accompanying drawings.

[0017] In this example, the reef type is determined to be a single reef with 8 square meters of space, taking into account comprehensive factors such as reef strength, stability, and fish gathering effect. 3 Three-dimensional frame reef. Based on the manufacturer's environmental impact assessment report, the reinforced concrete reef unit weighs 3,884 kg, with 3,700 kg of C30 strength concrete, 183.86 kg of reinforcement, and HRB400 steel. The C30 concrete is prepared using a mix ratio of cement, sand, gravel, and water of 1:1.23:3.01:0.41, and is poured into a mold. The cold-formed steel frame reef unit weighs 1.84 tons, made from hot-rolled strip steel coils with a yield of 96%, and is welded together. Shells are cleaned and calcined to remove water and organic impurities, then crushed and ground into fine aggregate with a particle size of less than 4.75 mm. This aggregate is used to replace 20% of the fine aggregate in the reinforced concrete reef, assuming the impact on the overall performance of the concrete does not exceed 5%. Converter slag, which accounts for 70% of the total slag produced by steelmaking converters, is used to replace 20% of the cement in the concrete after being pretreated using a hot-suffocating method. The process flow of cold-formed steel reef production, reinforced concrete reef production, shell pretreatment and hot-stifling steel slag pretreatment are as follows: Figures 1 to 4 shown.

[0018] CML2001-Jan.2016 was selected as the impact assessment method for this example. The environmental impact types include: Abiotic Resource Depletion Potential (Elements) (ADP e ), Abiotic Resource Depletion Potential (Fossil) (ADP f ), acidification potential (AP), eutrophication potential (EP), freshwater aquatic ecotoxicity potential (FAETP), global warming potential (GWP), human toxicity potential (HTP), marine aquatic ecotoxicity potential (MAETP), ozone depletion potential (ODP), photochemical smog formation potential (POCP), and terrestrial ecotoxicity potential (TETP). The results are as follows: (For ease of description, the four types of reefs are briefly described as steel reef, concrete reef, shell reef, and steel slag reef)

[0019] 1. The total environmental impact of producing 10,000 individual reefs, each measuring 2m×2m×2m, is as follows: steel reefs > shell reefs > concrete reefs > steel slag reefs. Greenhouse gas emissions are: 4.54E+08kgCO2eq for steel reefs, 6.72E+06kgCO2eq for shell reefs, 6.68E+06kgCO2eq for concrete reefs, and 5.66E+06kgCO2eq for steel slag reefs. Steel reefs have the highest environmental impact potential, with carbon emissions primarily coming from electricity consumption during the production and processing of the raw material, hot-rolled steel coils. The large amount of electricity and fossil energy consumed in the production of hot-rolled steel coils results in high global warming potential (GWP) and human toxicity potential (HTP). The environmental impact potential of cement production, the raw material for reinforced concrete reefs, accounts for 94.15% of the total environmental impact potential of concrete reef production, with total carbon emissions reaching 6.4E+06kgCO2eq and a high marine aquatic ecotoxicity potential (MAETP). Active exploration of alternative materials and energy-saving measures is recommended.

[0020] 2. The environmental impact potential of steel slag pretreatment is 4.49E-08, with carbon emissions of 2.02E+05kgCO2eq; the environmental impact potential of shell pretreatment is 1.00E-07, with carbon emissions of 3.2E+04kgCO2eq. While the carbon emissions from the steel slag pretreatment process are high, its overall environmental impact potential is low. Replacing 20% ​​of cement in concrete reefs after pretreatment reduces the overall environmental impact potential by 18%, demonstrating significant emission reduction benefits from waste recycling. However, the environmental impact potential of shell reefs is slightly higher than that of concrete reefs. This is primarily due to the relatively low environmental impact potential of the fine aggregate produced during the pretreatment process, making the energy conservation and emission reduction benefits of shell resource utilization less significant. Furthermore, the relatively high energy consumption of the pretreatment process leads to higher carbon emissions. Further research on the pretreatment process in shell resource utilization is needed to reduce energy consumption and environmental emissions.

[0021] Through analysis, the energy consumption and environmental emissions of artificial reef production processes using different materials were quantified, identifying high-pollution production links. The energy consumption of waste pretreatment and the energy conservation and emission reduction effects of resource utilization were clarified, providing a reference for the selection and optimization of artificial reefs.

Claims

1. A method for screening artificial reefs based on environmental impact, comprising the following steps: (1) Determination of objectives and scope: Considering the scope of use, performance, and fish attraction effect, four artificial reef materials were selected, including reinforced concrete, steel, concrete made by replacing 20% ​​of fine aggregate with shell powder, and concrete made by replacing 20% ​​of cement with steel slag. The input and output of materials within the system boundary include: Energy production and use, raw material production and use, and pollutant emissions during the production phase; The functional unit is defined as the production of 10,000 individual reefs, each measuring 2m x 2m x 2m. The resource consumption and environmental emissions of the four artificial reef production processes were calculated separately. (2) Inventory analysis: The raw material, resource, energy consumption, and waste gas emission data for the production of the four artificial reefs, as well as the consumption data for the two production waste pretreatment processes, were obtained from the enterprise feasibility study report, environmental impact assessment report, and published relevant references; the upstream traceability data for the raw material and energy manufacturing process were obtained from the professional database built into the life cycle assessment analysis tool GaBi software; (3) Impact assessment method: Based on the inventory data, calculations were performed using GaBi software and GaBiDatabase database modeling to establish four artificial reef production models, namely, cold-formed steel frame reef, reinforced concrete reef, concrete reef with shell powder replacing 20% ​​of fine aggregate, and concrete reef with steel slag replacing 20% ​​of cement. The pretreatment processes of shell and steel slag were added to the model through upstream tracing of raw materials. The CML2001-Jan.2016 evaluation method was used for normalized calculations. Energy consumption input, pollution output, and ecological damage were taken as the research contents. Based on the life cycle inventory of the four artificial reef materials, a characterization and normalization analysis was performed. The environmental impact potential of each type of indicator was calculated, and the environmental impact of the production of different reef materials was identified and quantitatively evaluated. (4) Result analysis: Evaluate the results of the impact assessment, compare the energy consumption and environmental impact of the four materials during their life cycles, identify the consumption of two waste materials, shell powder and steel slag, in the pretreatment process, judge the environmental friendliness of the four materials and propose corresponding improvement measures.

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