Ozone Layer Depletion Potential Research Articles

Evaluating the environmental and economic performance of biological and advanced biological wastewater treatment plants by life cycle assessment and life cycle costing.

The primary objective of this study is to assess and establish benchmarks for environmental and economic sustainability of biological and advanced biological wastewater treatment plants (WWTPs) with different treatment technologies and characteristics. Furthermore, the study aims to determine the beneficial role of WWTPs to reduction of eutrophication potential. Environmental and economic sustainability of ten municipal WWTPs was assessed using life cycle assessment (LCA) and life cycle costing (LCC). In the first section of the study, LCA was performed to determine the environmental performance of the WWTPs. Furthermore, net environmental benefit (NEB) approach was implemented to reveal the beneficial role of WWTPs to eutrophication potential. In the subsequent section, LCA-based LCC was conducted by integrating the results of LCA. The most significant environmental impact was determined as marine aquatic ecotoxicity, which is highly affected from the generation and transmission of electricity consumed in the WWTPs. Wastewater recovery and co-incineration of sewage sludge in cement kiln ensure significant environmental savings on ozone layer depletion, human toxicity, acidification, photochemical oxidation, and abiotic depletion (fossil fuel) potential. Considering NEB approach, the highest NEB values were found for the WWTPs with the higher organic load and nutrient concentration in the influent. The results of LCC in WWTPs varied between 0.21 and 0.53 €/m3. External (environmental) costs were evaluated higher than internal (operational) costs for all selected WWTPs. While eutrophication was the highest among environmental costs, electricity cost was the highest among operational costs for almost all WWTPs.

Importance of Strategic Environmental Assessment (Sea) Process and Environmental Health Impact Assessment (Ehia) Process Towards Sustainable Climate Change And Control

Importance of Strategic Environmental Assessment (Sea) Process and Environmental Health Impact Assessment (Ehia) Process Towards Sustainable Climate Change And Control

Towards sustainable production of sesame products: Comparison of traditional and modern production systems via a life cycle assessment approach

Burgeoning ecological crises of food production sector has made the environmental impact evaluation of various food products a sustainability imperative. Specifically, in pursuit of identifying a sustainable production model of high-demand food items, implementing a comparative life cycle assessment of various production approaches is of paramount importance. The energy consumption and environmental impacts of manufacturing two popular sesame products, Tahini (milled sesame paste) and Halva (sweetened sesame paste) in Iran was realized by using life cycle assessment methodology. In this regard, two production systems of traditional and modern, based on sesame cultivation and processing seeds were modeled. Moreover, production of milling stone, as the main instrument in Tahini and Halva production, was evaluated within the boundary of each product system. The highest energy used pattern and carbon footprint were attributed to the traditionally produced Tahini with 89.3 MJ/kg and 12.4 kg CO2eq/kg respectively; while, the lowest results were associated with modern-based Halva production with 47.8 MJ/kg and 5.4 kg CO2eq/kg. Compared to the traditional method, modern production of tahini was found to increase acidification potential and ozone layer depletion potential the most, with 73.1 g SO2eq and 0.735 mg R11eq respectively. Production of milling stone was the predominant hotspot for all products in traditional and modern systems, with average of 56% and 45% contribution to the total energy used, and 75% and 71% contribution to the carbon footprint of products in the former and latter systems respectively. Moreover, implementation of agrivoltaics system and circular economy-based milling stone as the alternative scenarios were evaluated from LCA perspective, which demonstrated that adoption of alternative milling stone could reduce the impact results significantly. It is believed that the novel evaluation framework of this study could serve as an example for future LCA studies to expand the common routine of evaluation and include production of instrument within the product's system boundary.

A cutting-edge tool for sustainable environmental management through life cycle assessment

The purpose of this study is to implement a novel Life Cycle Analysis (LCA) model in a software (called SharifLCA) that can overcome the disadvantages of current models. This software can assess environmental impact categories such as the impacts of carcinogenic, non-carcinogenic including cardiovascular and respiratory diseases, climate change (in various climate scenarios), ozone layer depletion potential including cataract and skin cancer, global warming potential, and resource depletion throughout the system life cycle. The model has the ability to consider different parameters affecting the results of LCA, such as the population affected by pollution, health risk assessment parameters, characteristics of pollution resource, and meteorological and topological data of the region. Furthermore, the life cycle environmental impacts of an electricity generation system are evaluated using the SharifLCA software under different scenarios. The results showed that the human health effect is higher when using fuels with lower quality. Moreover, the impacts of the carbon capture and storage system on environmental impact categories in different sectors of the system's life cycle are evaluated. In addition, the model has the ability to consider different parameters affecting the results, such as the population affected by pollution, health risk assessment parameters, characteristics of pollution resources, and meteorological and topological data. Therefore, the SharifLCA software can significantly increase accuracy in assessing local health impacts. The model presented in this study will be of great interest for researchers and policy-makers to increase the accuracy of LCA results.

Readjusting the climate change hyperfocus: how expanding the scope of impact categories will affect the evaluation of wood buildings

The sole focus on reducing the climate impact of dwellings by using wood is neglecting other impacts on nature. Therefore, this study clarifies the potential burden shift by considering ten more impact categories than greenhouse gas emissions. It assesses four wood buildings and one reference concrete building by using the method of life cycle assessment. What stands out is that wood dwellings perform better than the concrete building in most impact categories except for abiotic depletion potential and ozone layer depletion potential (ODP). The latter also experiences an impact increase when wood is used to decrease climate impact as global warming potential (GWP). The wood dwellings have a general inverse correlation between GWP ranking and ODP and some resource use indicators where plastics and cement-based materials influence the latter. Bio-based materials’ contribution to acidification and eutrophication is more considerable than to GWP. Upon the findings, increased inclusion of impact categories among researchers and practitioners must follow to expand the knowledge base. A foundation for future conscious decisions of using wood in dwellings and the challenging debate of reaching consent of which other impact categories should attain focus for being improved.

Prospective life cycle assessment of CO2 conversion by photocatalytic reaction

CO2 conversion is gradually seen as a better way for society to effectively use carbon sources and avoid climate crisis associated with fossil CO2 emissions. And the decision to deploy CO2 technology scale should be relied on its environmental impact. In this work, life cycle assessment model evaluates the environmental performance of CO2 conversion by photocatalytic reaction process with two different catalysts (NiAl-LDH and Co-ZIF-9). Six impact categories considered in this analysis, include climate change, acidification potential, depletion of abiotic resources, eutrophication potential, ozone layer depletion potential, and photochemical oxidation potential. Results indicated that CO2 conversion with Co-ZIF-9 photocatalyst has a better environmental impact than the NiAl-LDH photocatalyst route. Moreover, the Co-ZIF-9 catalyst scenario also has a lower total environmental burden than the conventional CO production route. Sensitivity analysis shows that recycle performance of the catalyst is highly sensitive to the production process in two scenarios. This study could provide a framework for robust decisions in CO2 conversion by photocatalytic reaction, which is useful for policymakers to decide the feasibility of industrialization.

Prospective life cycle environmental impact assessment of renewable energy-based methanol production system: A case study in China

Integrating renewable electricity and green hydrogen with CO2 utilization to produce chemicals has drawn much attention due to its low carbon emission characteristics. The goal of this paper is to investigate the environmental sustainability of producing a steady hourly output of methanol by utilizing electricity and hydrogen produced via renewable energy resources, and CO2 captured from a coal-fired power plant located in Inner Mongolia, China. Six renewable energy-based electricity and hydrogen systems are considered based on photovoltaic, wind turbines and combinations thereof, including battery and grid technologies. The environmental impact indicators of these system are compared comprehensively through life cycle assessment approach, including not only global warming potential but also fossil fuel depletion, water & soil & air pollution indices and human health index. The results indicate that the most environmentally friendly system is Case B2 which uses photovoltaic to produce hydrogen and electricity, with battery for energy storage and excess electricity sold back to grid. It shows apparently the best sustainability performance in global warming potential, which is 0.105 kg CO2-eq per kg methanol. In general, the proposed six systems outperform conventional methanol production systems in terms of global warming potential and abiotic depletion potential, with reductions ranging from 74% to 92% and 51.1%–73.8% respectively, but they have high levels in other environmental sustainability indicators such as human toxicity, eutrophication potential, and ozone layer depletion potential due to the photovoltaic electricity generation unit. The findings highlight that it is essential to consider a comprehensive range of environmental sustainability indicators when developing renewable energy-based methanol systems on a large scale.

Optimization model for selecting optimal prefabricated column design considering environmental impacts and costs using genetic algorithm

Prefabricated columns are commonly used in construction projects due to their advantages, such as high quality, fast construction, environmental friendliness, and cost-effectiveness. Toward achieving the minimization of environmental impacts and costs through the prefabricated system at the same time, the optimal design should be conducted during the pre-construction phases. Therefore, this research aims to develop an optimization model that uses a genetic algorithm to select optimal prefabricated column designs considering both environmental impacts and costs. This study was conducted in four steps: (i) Data collection, (ii) Calculation of environmental impacts, (iii) Economic assessment, and (iv) Optimization using a genetic algorithm. The results showed that the average environmental impacts for global warming potential (GWP), ozone layer depletion potential (ODP), acidification potential (AP), eutrophication potential (EP), photochemical ozone creation potential (POCP), and abiotic depletion potential (ADP), were 8382.10 kg-CO2, 1.76 × 10−4 kg-CFC-11, 11.03 kg-SO2, 1.89 kg-PO43-, 6.94 kg-C2H4, and 47.60 kg-sb, respectively, with an integrated value of $177.14. The average total cost of the prefabricated column was $4591.17. The overall environmental impacts and costs of the prefabricated columns were $26,020.37 and $680,477.36, respectively, whereas the optimal columns were $19,219.56 and $492,708.32, representing reductions of 26.14% and 27.59%, respectively. The implications of this research are of great importance for sustainable construction practices, as it provides a practical framework for selecting optimal prefabricated column designs that simultaneously minimize environmental impacts and costs. The integration of genetic algorithms within the optimization model enables the identification of environmentally friendly and cost-effective solutions, contributing to the overall reduction of environmental impacts associated with construction activities.

Komparasi Kinerja AC Kendaraan dengan Menggunakan Refrigeran R-134a, dan R-290

The development of vapor compression refrigeration systems currently depends on the issue of environmental problems related to ozone layer depletion (ODP) and global warming potential (GWP). In addition to environmental issues, low energy use is also in the spotlight of researchers. To solve the problem of refrigeration development, natural refrigeration, especially hydrocarbons, is the focus of attention. Hydrocarbons are refrigerants that have excellent properties to be natural refrigerants. This study aims to compare the performance of refrigerant R-134a with R-290. The research used a standard vapor compression refrigeration system with a TEV-type expansion valve. The system performance is seen through compression, refrigeration effect, and COP with variations in compressor rotational speed of 1000 rpm, 1500 rpm, and 2000 rpm. The results showed that the compression work, refrigeration effect, and coefficient of performance (COP) of R-290 had a more excellent value. R-290 produces the highest compression work at a 2000 rpm compressor speed of 33.34 kJ/kg for the refrigeration effect at 1000 rpm of 353.33 kJ/kg and COP at 1500 rpm 12.32.

An Analysis of Greenhouse Gas Reduction effect of Automotive Engine Re-manufacturing throug Whole Process Analysis

In this research, through LCA analysis, the environmental impact of automotive engine manufacturing and re-manufacturing was analyzed from the perspective of the entire process, and the greenhouse gas reduction effect was calculated based on this. The amount of greenhouse gas emitted from the process of acquiring and manufacturing raw materials for automotive engines is about 3,473 kg for new manufacturing and 872 kg for re-manufacturing. Thus, the amount of greenhouse gas reduction by engaging in re-manufacturing is about 2,601 kg; the analysis shows a reduction effect in each part of the entire process except for the processing stage. As a result of the LCA weighted analysis, the environmental impact of new product manufacturing was found to be 1.07E+03 Eco-point, and it was 2.67E+02 Eco-point for re-manufacturing. The share of GWP(Global Warming Potential) among the six major impact categories(Abiotic Depletion Potential, Acidification Potential, Eutrophication Potential, Global Warming Potential, Ozone-layer Depletion Potential, Photochemical Oxidant Creation Potential) as high at 99.72%(new manufacturing) and 99.68%(re-manufacturing).

Valorization of biogas from the anaerobic co-treatment of sewage sludge and organic waste: Life cycle assessment and life cycle costing of different recovery strategies

Nowadays, biogas produced from the anaerobic digestion of biowaste is considered a valuable renewable energy source to implement the transition to a climate-neutral society. Recently, biogas upgrading to biomethane, instead of the usual co-generation of heat and electricity (CHP), has been an attractive option, as biomethane can be used for different purposes. This study performed the life cycle assessment (LCA) and life cycle costing (LCC) of different scenarios for the valorization of the biogas produced from the anaerobic co-digestion (AcoD) of secondary sewage sludge (SS) and organic fraction of municipal solid waste (OFMSW), pre-treated by an anaerobic dark co-fermentation (DF) process. Four configurations were compared, exploring the recovery of one or more of the following: heat, electricity and biomethane. Furthermore, two sensitivity analyses were performed on LCA analysis, considering the use of the produced biomethane as a fuel for transport and the European electricity mix expected by 2050, respectively. The use of biogas for CHP was the most environmentally friendly solutions in 8 out of 11 impact categories provided by the CML-IA baseline method; however, biogas upgrading-based scenarios showed less impacts in relevant categories, such as global warming potential (up to −1.14E+05 kg CO2 eq. y−1) and ozone layer depletion potential (up to −4.73E-01 kg CFC-11 eq. y−1). Sensitivity analyses confirmed that the biogas upgrading processes should have generally a lower impact on climate change than CHP systems. Furthermore, the use of biomethane to replace petrol resulted to be the best option in terms of global warming potential (up to −5.67E+05 kg CO2 eq. y−1). All the proposed configurations represented economically sustainable projects, as they reported positive net present values (NPV) in 20 years (up to 10,518,291 €). Biogas upgrading-based scenarios showed the highest NPVs; nevertheless, the combined production of heat, electricity and biomethane was the most cost-effective option, thanks to biomethane revenues and electricity sales, despite the latter being modest. In conclusion, contrary to most of the previous studies in the literature, we found that CHP should not be neglected, as the optimal configuration may lie in the combined recovery of biomethane, electricity and heat.

Life cycle assessment of olive pomace gasification for an up-draft fixed bed gasifier system

Biomass gasification has been considered as an important renewable energy alternative to deal with the environmental problems originating from fossil fuels and climate change effects. Olive pomace as a by-product of the olive oil production process is a significant biomass source. Although gasification technology is accepted as an environmentally friendly power system, the studies to determine its environmental impact via Life Cycle Assessment (LCA) are very limited. LCA is a key tool to evaluate all environmental impacts from the beginning to the end of the process. The aim of this study is to assess the overall environmental impacts of the olive pomace gasification for electricity generation and evaluation of its solid by-products namely biochar and tar. Four scenarios were compared to estimate the environmental impacts of gasification by-products with a LCA approach, following to the cradle-to-grave approach. The production of olive, olive pomace generation during its processing for olive oil production, gasification of olive pomace, construction of the gasifier, gas cleaning system and syngas composition have been included in the evaluations. It is clear from the analysis results that the scenarios have very low impact values in the case of beneficial usage of biochar in different industries. In terms of ozone layer depletion potential (2.74 × 10 −6 kg CFC11 eq) and global warming potential (36.99 GWP100a), the paramount scenario from an environmental viewpoint is the scenario having the biochar and tar usage as a resource in another industry.

Environmental impact assessment of VOC emissions from biomass gasification power generation system based on life cycle analysis

The control of volatile organic compounds (VOC) is one of the key challenges in biomass combustion. This study aims to establish a process-based model to assess the life cycle VOC emissions of a biomass gasification power plant in China. In this study, the life cycle assessment (LCA) method was used for the first time to evaluate the direct VOC emissions and indirect VOC emissions from biomass gasification power generation. The whole system consists of three parts: biomass waste feedstock system, gasification power generation system and waste treating system. And waste treatment mainly includes waste water treatment and waste gas treatment. Results show that the life cycle VOC emissions intensity from the biomass gasification power generation process as a whole are calculated as 57.05 g/MWh, without considering the influence of air pollution control devices’ (APCDs). With the implementation of APCDs, this value will be reduced to 7.08 to 22.83 g/MWh, reducing by 12.41 to 40.02 %. In the scenario analysis, APCDs with different combinations of installations are evaluated by applying the practical engineering applications. The scenario of selective catalytic reduction (SCR) and wet electrostatic precipitation (WESP) can achieve the best removal effect, under which VOC emissions intensity can achieve 34.22 g/MWh, and the indirect emissions account for 46.15 % of life cycle VOC emissions, which are mainly from wastewater treatment process. The photochemical ozone generation potential and ozone layer depletion potential from emitted VOC are the two largest in this scenario, accounting for 17.71 % and 8.59 % respectively. If all open burning and indoor combustion of biomass in China can be replaced by the biomass gasification power generation technology, the relevant national VOC emissions reduction potential could reach up to 1.95 Mt/year. Among all the provinces, Heilongjiang, Anhui, Henan, Shandong and Jilin are the five provinces with the highest VOC emissions reduction potential. The influence of key input variables on overall VOC emission is also analyzed in this study. Based on the results, the optimal direction and possible measures to reduce VOC emission are put forward. This study is of great significance for the accurate control of VOC emissions in biomass gasification power generation technology.

Life cycle assessment of construction and demolition waste-based geopolymers suited for use in 3-dimensional additive manufacturing

This study performs a life cycle assessment (LCA) on a novel process to produce geopolymer binders for 3-dimensional additive manufacturing (3D-AM). The method utilises construction and demolition waste (CDW) [hollow brick (HB), red clay brick (RCB), roof tile (RT), and glass (G)] as a sustainable resource for geopolymers production to replace Portland cement. The life cycle assessment is performed to identify hotspots (relevant processes or raw material) to improve the environmental performance of the whole process at an early stage of development and to evaluate the environmental impacts of energy, water, and waste emissions at various points in the life cycle. The CDW requires crushing, milling/grinding, and mixing with electrical input to produce the geopolymer binders. The alkali activators' composition [6.25M NaOH, 10% Ca(OH) 2 ] is selected as the base case for the assessment. The life cycle impact assessment (LCIA) results show the environmental impacts to be 635 (kg CO 2 eq.), 5.06 (kg SO 2 eq.), 0.104 (kg N eq.), 3.14E-10 (kg N eq.), and 12.2 (CTUe.) for the global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), and Ecotox air respectively for 1 m 3 of geopolymer binder produced. Electricity contributes over 60% to the GWP, AP, EP, and Ecotox Air; therefore, a sensitivity analysis is performed with varying sources of renewable electricity. Also, compared to ordinary Portland cement (OPC), the GWP for the geopolymer binder produced is 21% less.

A closed-loop recycling process for carbon fiber-reinforced polymer waste using thermally activated oxide semiconductors: Carbon fiber recycling, characterization and life cycle assessment

The objective of this study is to investigate the properties of recycled carbon fiber (rCF) and its environmental impact, with a specific focus on the energy consumption of the recycling process based on the use of thermally activated oxide semiconductors (TASC). The mechanical and surface properties of rCF obtained under the optimal process parameters were characterized. The life cycle assessment method was used to evaluate the environmental impact of a closed-loop recycling process for carbon fiber-reinforced polymer (CFRP) waste using TASC. The results indicated that the decomposition rate of resin was 95.5 %, and no carbonaceous solid was generated. The gaseous produced of the recycling process were mainly CO2 and H2O, and no liquid products were produced. The surface oxidation degree of rCF was relatively slight. COOH was generated on the surface of rCF, which was conducive to improving the interfacial adhesion viscosity with resin. The monofilament tensile strength of rCF was maintained above 97 %. Compared with landfill and incineration, CFRP waste recycling using TASC can make global warming potential, acidification potential and eutrophication potential reduced by 28 %, 32 %, and 25 %, respectively. Ozone layer depletion potential, human toxicity potential and terrestrial ecotoxicity potential in disposing CFRP waste using TASC were 30 %, 21 % and 41 % of that using pyrolysis, respectively. The energy consumption in carbon fiber recycling by TASC was only 23 % of that in virgin carbon fiber manufacturing. TASC is found to be a promising potential strategy for managing CFRP waste.

Bioenergy from anaerobic digestion plants: Energy and environmental assessment of a wide sample of Italian plants

This study assesses the energy and environmental performances of electricity produced from Italian anaerobic digestion coupled with combined heat and power plants. The Life Cycle Assessment methodology is applied to a set of plants characterised by different power sizes (from 100 to 999 kW) and feedstock compositions (variable rates of agricultural products and by-products). Then, the average eco-profile of the produced electricity is compared with electricity produced by the national grid and photovoltaic panels.The analysis allows detection of the combinations of size and feedstock with the lowest impacts. They correspond to small and medium plants mainly fed by organic by-products.In addition, compared to electricity from the grid, the average biogas electricity is characterised by the lowest contribution in impacts categories, such as abiotic depletion potential and ozone layer depletion potential, while largest in acidification and eutrophication. Focusing on global warming potential and cumulative energy demand fossil, the impacts of average biogas electricity (155 kgCO2eq/MWh and 172 MJ/MWh) are about 35 % and 38 % of that generated by the grid. Furthermore, it could generate 47 % less of the impact in the abiotic depletion elements category of the solar system.To enhance the farms' environmental and economic sustainability and balance the electric grid, these outcomes point out that biogas electricity produced from the agriculture and livestock sector can contribute to the decarbonisation and self-sufficiency of European countries.The results strictly depend on the operative conditions and can aid policymakers at the global level in improving the energy supply security and sustainability. Further, they provide reliable information to stakeholders to select the most sustainable solution, according to the feedstock type, power supply, and management.

Conversion of Waste Biomass into Activated Carbon and Evaluation of Environmental Consequences Using Life Cycle Assessment

In this article, activated carbon was produced from Lantana camara and olive trees by H3PO4 chemical activation. The prepared activated carbons were analyzed by characterizations such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller, X-ray diffraction, thermogravimetric analysis, and Fourier transform infrared spectroscopy. H3PO4 is used as an activator agent to create an abundant pore structure. According to EDX analysis, the crystalline structure destroys and increases the carbon content of the olive tree and Lantana camara by 77.51 and 76.16%, respectively. SEM images reveal a porous structure formed as a result of H3PO4 activation. The Brunauer–Emmett–Teller (BET) surface area of the olive tree and Lantana camara activated carbon was 611.21 m2/g and 167.47 m2/g, respectively. The TGA analysis of both activated carbons shows their thermal degradation starts at 230 °C but fully degrades at temperatures above 450 °C. To quantify the potential environmental implications related to the production process of the activated carbon (AC) from olive trees, the life cycle assessment (LCA) environmental methodology was employed. For most of the tested indicators, chemical activation using H3PO4 showed the greatest ecological impacts: the ozone layer depletion potential (42.27%), the acidification potential (55.31%), human toxicity (57.00%), freshwater aquatic ecotoxicity (85.01%), terrestrial ecotoxicity (86.17%), and eutrophication (92.20%). The global warming potential (5.210 kg CO2 eq), which was evenly weighted between the phases, was shown to be one of the most significant impacts. The total energy demand of the olive tree’s AC producing process was 70.521 MJ per Kg.

Major Building Materials in Terms of Environmental Impact Evaluation of School Buildings in South Korea

This study aimed to analyze the major building materials in terms of environmental impact evaluation of school buildings in South Korea. Three existing school buildings were selected as the analysis targets, and building materials were analyzed in terms of cumulative weight and six environmental impact categories (global warming potential, abiotic depletion potential, acidification potential, eutrophication potential, ozone-layer depletion potential, and photochemical oxidation potential). The materials were analyzed from an environmental perspective after integrating the six environmental impact categories into the environmental costs. From the analysis, nine major building materials, including ready-mixed concrete, concrete bricks, aggregate, rebar, cement, stone, glass, insulating materials, and wood, were selected for the school buildings. These analysis results can be used as a streamlined evaluation of the environmental impacts of school buildings. It is thought that the simplified life cycle assessment will help make decisions considering environmental characteristics in the early stage of the construction project. Additionally, it will be possible to make LCA efficient in terms of time and cost, one of the largest constraints of the existing building LCA, and effective reduction in the environmental load.

Construction and demolition waste-based geopolymers for built-environment: An environmental sustainability assessment

In this study, the environmental sustainability assessment has been performed for producing geopolymer binders for 3-dimensional additive manufacturing (3D-AM). To substitute Portland cement, the technique utilizes building and demolition waste (CDW) [hollow brick (HB), red clay brick (RCB), roof tile (RT), and glass (G)] as a sustainable resource for geopolymers synthesis. A life cycle assessment aims to determine hotspots (relevant processes or raw materials) early in the product development process to enhance the entire process's environmental performance and evaluate the ecological impact of energy, water, and waste emissions. The CDW requires crushing, milling/grinding, and mixing using the input power to make the geopolymer binders. The life cycle impact assessment (LCIA) results show the environmental impacts to be 635 (kg CO2 eq.), 5.06 (kg SO2 eq.), 0.104 (kg N eq.), 3.14E-10 (kg N eq.), and 12.2 (CTUe.) for the global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), ozone layer depletion potential (ODP), and Ecotox air respectively for 1 m3 of geopolymer binder produced.

Life cycle assessment for the milling operation of titanium alloy (Ti6Al4V)

There is a growing interest in titanium alloy for medical, aerospace, biomedical, automotive and rail applications due to its desirable properties such as its high strength to weight ratio and corrosion resistance ability. However, its low thermal conductivity can affect the energy consumption and rate of material removal thereby affecting the overall sustainability of the cutting operation. Hence, this study employs the Life Cycle Assessment (LCA) model for the investigation of the midpoint and endpoint characteristics of the milling operation of titanium alloy (Ti6Al4V) under the cooling and non-cooling conditions. The input and output of the milling process serve as the life cycle inventory. The Environmental Impact Assessment (EIA) was carried out with the aid of the Umberto NXT universal with database Eco-invent version 3.0. (CML 2001 and Impact 2002+ valuation standards). For the mid-point assessment, the results obtained indicate that the ozone layer depletion and global warming potential were the most significantly impacted potentials during the milling operation. However, the potential impacts were more significant under the cutting operation without cooling. The endpoint assessment for a cutting operation with cooling, contributes 15%, 12% and 9% to the global warming, eco system and human health toxicity respectively. The cutting operation without cooling contributes 18%, 16% and 9% to the global warming, eco system and human health toxicity respectively. This study provides an insight into the sustainability of titanium alloy during the milling process in terms of the energy requirements and environmental friendliness of the process.