Environmental impact assessment of China’s primary aluminum based on life cycle assessment

Assessing and accounting for material consumption and environmental impact are necessary to measure environmental externalities of the aluminum industry and to construct an ecological civilization.In this research,life cycle assessment(LCA)theory was used to assess the environmental impact of primary aluminum based on the lime soda Bayer process and different power generation modes,and the sources and distributions of the four selected impact categories were analyzed.The results show that,(1)Negative environmental impact of aluminum industry generally occurs from alumina extraction,carbon anode fabrication and electrolysis,particularly electrolysis and alumina extraction.Primary energy demand(PED),water use(WU),global warming potential(GWP)and freshwater eutrophication potential(FEP)are main environmental impact categories.(2)The environmental load with thermal power is higher than that with hydropower,e.g.,for the former,the greenhouse gas emission coefficient of 21800 kg CO2 eq/t(Al)will be generated,while for the latter,4910 kg CO2 eq/t(Al)will be generated.(3)Both power mode methods reflect the energy structure,whereas direct emissions reflect the technical level,indicating the potential for large energy savings and emission reductions,and some policies,related to clean power,energy efficiency and technological progress,should be made for emission reduction.

Life cycle environmental impact assessment of biochar-based bioenergy production and utilization in Northwestern Ontario,Canada

Biochar-based bioenergy production and sub- sequent land application of biochar can reduce greenhouse gas emissions by fixing atmospheric carbon into the soil for a long period of time. A thorough life cycle assessment of biochar-based bioenergy production and biochar land application in Northwestern Ontario is conducted using SimaPro Ver. 8.1. The results of energy consumption and potential environmental impact of biochar-based bioenergy production system are compared with those of conventional coal-based system. Results show that biocbar land application consumes 4847.61 MJ per tonne dry feedstock more energy than conventional system, but reduces the GHG emissions by 68.19 kg CO2e per tonne of dry feed- stock in its life cycle. Biochar land application improves ecosystem quality by 18 %, reduces climate change by 15 %, and resource use by 13 % but may adversely impact on human health by increasing disability adjusted life years by 1.7 % if biomass availability is low to medium. Replacing fossil fuel with woody biomass has a positiveimpact on the environment, as one tonne of dry biomass feedstock when converted to biochar reduces up to 38 kg CO2e with biochar land application despite using more energy. These results will help understand a comprehensive picture of the new interventions in forestry businesses, which are promoting biochar-based bioenergy production.

Life cycle assessment in the environmental impact evaluation of urbandevelopment--a case study of land readjustment project,Hyogo District, Japan

In this paper, the Life Cycle of Urban Development was firstly analyzed, and the phases of Life Cycle Assessment applied to Urban Development (ULCA) were described. As a case study, ULCA was applied in the environmental impact assessment of the land readjustment project of Hyogo District of Saga, Japan. In addition, mitigation proposals for reducing CO2 were also presented and the relevant environmental ef-fects were simulated.

Investigation of the environmental impacts of steel deck pavement based on life cycle assessment

To investigate the environmental impacts of steel deck pavement through the whole life cycle,the steel deck pavement was divided into five stages:raw materials production,asphalt mixture mixing,pavement construction,operation management,and pavement removing stage.Based on the process-based life cycle assessment(PLCA)method,the calculation methods of energy consumption and gas emissions of two typical steel deck pavement systems(EA+EA pavement and GA+SMA pavement)were determined.The data lists of two pavements were analyzed,and the calculation model was built.Four characteristic indices including primary energy demand(PED),global warming potential(GWP),acidification potential(AP)and respiratory inorganics(RI)were used to quantify the environmental impacts of two pavements.The results show that the environmental impact of the GA+SMA pavement is more than 1.3 times that of the EA+EA pavement.Moreover,the critical stage of energy-saving and emission-reduction of EA+EA pavement and GA+SMA pavement are the raw material production stage and asphalt mixture mixing stage,respectively.

Environmental impact assessment of magnesium alloy automobile hub based on life cycle assessment

In order to find out the impact of aluminum alloy hub replaced by the magnesium alloy hub on environment,the resource consumption,energy consumption and pollutant emission during hub production and their service life of the two types of hubs are investigated based on the life cycle assessment(LCA)theory.The results indicate that the adverse impact on environment can be effectively reduced by the application of magnesium alloy hubs.Compared with aluminum alloy hubs,the global warming potential(GWP)and human toxicity potential(HTP)are reduced by 39.6%and 24.0%,respectively.CO2 is the main pollutant in the life cycles of the two kinds of hubs,which is generated throughout the whole life cycle including the fabrication process and the service life,while the pollutants of particles mainly come from the fabrication stage.Compared with the aluminum alloy hubs,the green effect brought by magnesium alloy hubs is mainly due to the reduction of fuel consumption caused by weight loss.

Life cycle assessment for the "implicit" environmental impact of construction projects

The paper has established an assessment system and a quantitative calculation method of the 'implicit' environmental impact including environmental impact indicator,resources consumption indicator and energy consumption indicator. The quantitative calculation of the environmental impact indicator is based on the life cycle assessment system and the evaluation software BEES. The paper identifies normalization reference values and weights for 12 categories of the environmental impact. It also analyzes the environmental impact indicator in life cycle stages,raw materials,transportation,manufacturing,utilization,and end of life. A university refectory project is studied. The result has shown that human health,global warming and acidification are the first three environmental impacts in 12 categories. The environmental impact indicator per m2 of this project is 18.448×10-2 standard human equivalent weight. Moreover,97.3% of the total environmental impact occurs at the raw material stage,in which the most severe environmental impact is cancerous health effect; the global warming is the main impact at the transportation and manufacturing stages; the indoor air quality impact is at the usage stage.

Life-Cycle Impact Assessment of Air Emissions from a Cement Production Plant in Cambodia

Cement industrial emissions account for 32% of air pollution in Cambodia. With that in mind, we examined the environmental impact of Cambodia’s cement industry and identified ways that it could reduce air pollution. The study focused on raw material extraction and preparation, calcination, and cement preparation. Data for the life-cycle inventory were provided by the Kampot Cement Plant. Air emissions were assessed using EMEP/EEA and IPCC criteria, and the impact assessment used ReCiPe (2016). The baseline analysis revealed that calcination contributed the most air pollutants, so mitigation scenarios focused on alternative fuels only during the calcination stage of cement production: 1) 100% coal (S1);2) 93% coal and 7% biomass (S2);3) 85% coal and 15% biomass (S3);4) 70% coal and 30% biomass (S4);and 5) 50% coal and 50% biomass (S5). The results demonstrated that certain mitigation measures reduced major emissions and environmental damage. S5 had the best results, reducing CO2 by 49.97, NOx by 2.233, and SO2 by 49.333%;however, it increased PM2.5 by 19.60% and total heavy metal (Pb, Cd, Hg, As, Cr, Cu, Ni, Se, Zn) output by 28.113%. The results of the study showed reductions in serious health and environmental effects associated with climate change of 48.83%, ozone generation of 9.62%, and particulate matter formation of 28.80%. However, carcinogenic and non-carcinogenic human toxicity increased by 35.66%. Therefore, such mitigation effect would be benefit to carbon reduction target in Cambodia.

Life cycle assessment for waste acid treatment in zinc smelting

Lift cycle assessment(LCA)methodology was applied to evaluating and comparing two waste acid disposal processes in zinc smelting.The results indicate that environmental impacts of gas−liquid vulcanization technologies are human toxicity,abiotic depletion potential,and global warming risk,which are mainly caused in neutralizing−evaporating−crystallization unit and electrodialysis unit.As for traditional lime neutralization method,vulcanization unit is the main factor.In this regard,the total environmental impact of traditional lime neutralization method is much higher than that of gas−liquid vulcanization technologies.Furthermore,the sensitive analysis shows that electricity and sodium sulfide(60%)are sensitive factors in two waste acid disposal technologies.In addition,the total cost of disposing a functional unit waste acid in traditional lime neutralization process is nearly 27 times that of the gas−liquid vulcanization waste acid disposal technologies.

Life Cycle Assessment of Creosote-Treated Wooden Railroad Crossties in the US with Comparisons to Concrete and Plastic Composite Railroad Crossties

Creosote-treated wooden railroad crossties have been used for more than a century to support steel rails and to transfer load from the rails to the underlying ballast while keeping the rails at the correct gauge. As transportation engineers look for improved service life and environmental performance in railway systems, alternatives to the creosote-treated wooden crosstie are being considered. This paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties. This LCA includes a life cycle inventory (LCI) to catalogue the input and output data from crosstie manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to evaluate greenhouse gas (GHG) emissions, fossil fuel and water use, and emissions with the potential to cause acidification, smog, ecotoxicity, and eutrophication. Comparisons of the products are made at a functional unit of 1.61 kilometers (1.0 mile) of rail-road track per year. This LCA finds that the manufacture, use, and disposition of creosote-treated wooden railroad crossties offers lower fossil fuel and water use and lesser environmental impacts than competing products manufactured of concrete and P/C.

Life cycle assessment of HFC-134a production by calcium carbide acetylene route in China

HFC-134a is a widely used environment-friendly refrigerant.At present,China is the largest producer of HFC-134a in the world.The production of HFC-134a in China mainly adopts the calcium carbide acetylene route.However,the production route has high resource and energy consumption and large waste emission,and few of the studies addressed on the environmental performance of its production process.This study quantified the environmental performance of HFC-134a production by calcium carbide route via carrying out a life cycle assessment(LCA)using the CML 2001 method.And uncertainty analysis by Monte-Carlo simulation was also carried out.The results showed that electricity had the most impact on the environment,followed by steam,hydrogen fluoride and chlorine,and the impact of direct CO_(2) emissions in calcium carbide production stage on the global warming effect also could not be ignored.Therefore,the clean energy(e.g.,wind,solar,biomass,and natural gas)was used to replace coal-based electricity and coal-fired steam in this study,showing considerable environmental benefits.At the same time,the use of advanced production technologies could also improve environmental benefits,and the environmental impact of the global warming category could be reduced by 4.1%via using CO_(2) capture and purification technology.The Chinese database of HFC-134a production established in this study provides convenience for the relevant study of scholars.For the production of HFC-134a,this study helps to better identify the specific environmental hotspots and proposes useful ways to improve the environmental benefits.

Life Cycle Assessment of CCA-Treated Wood Highway Guard Rail Posts in the US with Comparisons to Galvanized Steel Guard Rail Posts

A cradle-to-grave life cycle assessment is done to identify the environmental impacts of chromated copper arsenate (CCA)-treated timber used for highway guard rail posts, to understand the processes that contribute to the total impacts, and to determine how the impacts compare to the primary alternative product, galvanized steel posts. Guard rail posts are the supporting structures for highway guard rails. Transportation engineers, as well as public and regulatory interests, have increasing need to understand the environmental implications of guard rail post selection, in addition to factors such as costs and service performance. This study uses a life cycle inventory (LCI) to catalogue the input and output data from guard rail post manufacture, service life, and disposition, and a life cycle impact assessment (LCIA) to assess anthropogenic and net greenhouse gas (GHG), acidification, smog, ecotoxicity, and eutrophication potentially resulting from life cycle air emissions. Other indicators of interest also are tracked, such as fossil fuel and water use. Comparisons of guard rail post products are made at a functional unit of one post per year of service. This life cycle assessment (LCA) finds that the manufacture, use, and disposition of CCA-treated wood guard rails offers lower fossil fuel use and lower anthropogenic and net GHG emissions, acidification, smog potential, and ecotoxicity environmental impacts than impact indicator values for galvanized steel posts. Water use and eutrophication impact indicator values for CCA-treated guard rail posts are greater than impact indicator values for galvanized steel guard rail posts.

Life Cycle Assessment of Different Sea Cucumber(Apostichopus japonicus Selenka) Farming Systems

The life cycle assessment was employed to evaluate the environmental impacts of three farming systems(indoor intensive, semi-intensive and extensive systems) of sea cucumber living near Qingdao, China, which can effectively overcome the interference of inaccurate background parameters caused by the diversity of economic level and environment in different regions. Six indicators entailing global warming potential(1.86 E + 04, 3.45 E + 03, 2.36 E + 02), eutrophication potential(6.65 E + 01,-1.24 E + 02,-1.65 E + 02), acidification potential(1.93 E + 02, 4.33 E + 01, 1.30 E + 00), photochemical oxidant formation potential(2.35E-01, 5.46E-02, 2.53E-03), human toxicity potential(2.47 E + 00, 6.08E-01, 4.91 E + 00) and energy use(3.36 E + 05, 1.27 E + 04, 1.48 E + 03) were introduced in the current study. It was found that all environmental indicators in the indoor intensive farming system were much higher than those in semi-intensive and extensive farming systems because of the dominant role of energy input, while energy input also contributed as the leading cause factor for most of the indicators in the semi-intensive farming system. Yet in the extensive farming system, infrastructure materials played a major role. Through a comprehensive comparison of the three farming systems, it was concluded that income per unit area of indoor intensive farming system was much higher than those of semi-intensive and extensive farming systems. However, the extensive farming system was the most sustainable one. Moreover, adequate measures were proposed, respectively, to improve the environmental sustainability of each farming system in the present study.

Carbon footprint accounting for cigar production processes: A life cycle assessment perspective

Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally.Cigarette factories are a key link in the tobacco industry’s production chain,and using data provided by a cigarette factory in China we conduct a life cycle assessment to account for the carbon footprint of cigar production in cigarette factories.The results of the assessment show that factory air conditioning is the most important contributor to the environmental load of the cigar manufacturing process,while electricity is the key factor that contributes the greatest envi‐ronmental load across all of the processes in the product life cycle.In addition,packaging,including small boxes and cigarette cartons,has a significant impact on the industry’s environmental footprint due to its use of raw materials.We find the carbon footprint of the entire production process for cigar products to be 383.59 kg CO_(2) eq.Based on our findings,we suggest ways to optimize cigar/cigarette factory processes to re‐duce carbon emissions that can help to promote sustainable development in related industries.

Life Cycle Assessment and Life Cycle Cost of Waste Management—Plastic Cable Waste

The main driver for recycling cable wastes is the high value of the conducting metal, while the plastic with its lower value is often neglected. New improved cable plastic recycling routes can provide both economic and environmental incentive to cable producers for moving up the “cable plastic waste ladder”. Cradle-to-gate life cycle assessment, LCA, of the waste management of the cable scrap is suggested and explained as a method to analyze the pros and cons of different cable scrap recycling options at hand. Economic and environmental data about different recycling processes and other relevant processes and materials are given. Cable producers can use this data and method to assess the way they deal with the cable plastic waste today and compare it with available alternatives and thus illuminate the improvement potential of recycling cable plastic waste both in an environmental and in an economic sense. The methodology applied consists of: cradle-to-gate LCA for waste material to a recycled material (recyclate);quantifying the climate impact for each step on the waste ladder for the specific waste material;the use of economic and climate impact data in parallel;climate impact presented as a span to portray the insecurities related to which material the waste will replace;and possibilities for do-it-yourself calculations. Potentially, the methodology can be useful also for other waste materials in the future.

Life cycle inventory analysis of CO_2 and SO_2 emission of imperial smelting process for Pb-Zn smelter

Based on the principle of life cycle assessment, CO2 and SO2 emission of Imperial Smelting Process in a certain zinc-lead smelter was analyzed by life cycle inventory method. According to the system expansion and substitution method, the environmental impacts of co-products were allocated among the main products of zinc, lead and sulfuric acid. The related impacts were assessed by use of Global Warming Potential （GWP） and Acidification Potential （ACP）. The results show that the GWP index from 1998 to 2000 is 11.53, 11.65, 10.93 tCO2-eq/tZn respectively, the ACP index decreases from 14.88 kgSO2-eq/tZn in 1998 to 10.99 kgSO2-eq/tZn in 2000. Power and electricity generation, followed by smelting and zinc distillation, are mainly responsible for GWP. Sintering individually affects ACP. Reduction in greenhouse gas emissions of the ISP may come from energy conservation measures rather than from technological developments. And recycling more secondary Pb and Zn materials effectively treated by ISP, and reducing the amount of primary metal are the main ways to put SO2 emission under control.

Exergy Efficiency and Environmental Impact of Electricity of a 620 MW-Natural Gas Combined Cycle

In the first part of this investigation, a Natural Gas Combined Cycle (NGCC) producing 620 MW of electricity was simulated using the commercial software Aspen Hysys V9.0 and the Soave-Redlich-Kwong (SRK) equation of state. The aim of this second part is to use exergy-based analyses in order to calculate its exergy efficiency and evaluate its environmental impact under standard conditions. For the exergy efficiency, the performance index under investigation is the exergy destruction ratio (yD). The results of the study show that the combustor is the main contributor to the total exergy destruction of the power plant (yD = 24.35%) and has the lowest exergy efficiency of 75.65%. On the other hand, the Heat Recovery Steam Generator (HRSG) has the lowest contribution to the exergy destruction (yD = 5.63%) of the power plant and the highest exergy efficiency of 94.37%. For the overall power plant, the exergy efficiency is equal to 53.28%. For the environmental impact of the power plant, the relative difference of exergy-related environmental impacts (rb) is utilized as the performance index for each equipment of the plant and the environmental impact of a kWh of electricity (EIE) is used to represent the performance index of the overall power plant. In agreement with the exergy analysis, the results indicate that the combustor and the HRSG have respectively the highest (rb = 32.19%) and the lowest (rb = 5.96%) contribution to the environmental impact. The environmental impact of a kWh of electricity of the power plant is 34.26 mPts/kWh (exergy destruction only), and 34.42 mPts/kWh (both exergy destruction and exergy loss).

废冰箱回收利用环境效益评估——基于IMPACT WORLD+方法

废电器是产生量大且增速快的一类固体废物.我国构建的废电器回收体系是实施碳达峰?碳中和的重要举措,但废电器回收利用体系的环境效益尚不清楚.利用IMPACTWORLD+方法,从不同环境影响类型出发评估废电器回收处理的环境效益,并通过损害类型指标量化评价.结果表明,废冰箱回收利用的损害类型指标“人体健康”和“生态环境质量”的结果分别为-10592.501EUR2015和-8211.357EUR2015,合计为-18803.857EUR2015,即环境收益相当于18803.857EUR2015.据此估算,中国2021年废电器回收处理体系中仅废冰箱回收利用的环境收益可达12.82亿EUR2015.研究结果表明废电器回收处理的环境收益十分可观,有望为废电器回收行业的可持续发展提供新的助力.

Environmental Impact Assessment for an Absorption Heat Transformer

This study presents the environmental impact assessment of an absorption heat transformer designed to recover 1 kW of thermal energy from each 2 kW of waste heat supplies. The net contribution of the heat transformer is a load avoided of 0.665 kg CO2 equivalents;the recovery process avoids 0.729 kg CO2 equivalents and the major contribution to the environment impacts is the pumping process with 0.0437 kg CO2 equivalents for each 1 kWh recovered. The study results show that absorption heat transformer is a good environmental option because it produces useful energy from waste heat and the final result is an environmental impact diminution.

A Comparative Environmental Evaluation of the Coal and Natural Gas Life Cycle

Natural gas and coal are the main primary energy resources used in the Romanian energy sector, 73.7% in 2011, taking into account the fuel imports. The objective of the article consists in analyzing all the processes along the coal and the natural gas life cycle in order to assess their overall environmental impact. Two energy technologies were analyzed, for each resource: the pulverized coal combustion with supra-critical parameters and CO2 capture unit and the natural gas combined cycle. Considering the functional unit of electricity production for 1 year, it was found that the natural gas combined cycle remains the more interesting energy technology from an environmental point of view. However, the pulverized coal with supra-critical parameters equipped with a CO2 capture unit has the lowest environmental impact on the climate change. The weakest point of the coal technology is its low efficiency.

Assessing environmental impact:Micro-energy network optimization in a Chinese industrial park

Micro-energy systems contribute significantly to environmental improvement by reducing dependence on power grids through the utilization of multiple renewable energy sources.This study quantified the environmental impact of a micro-energy network system in an industrial park through a life cycle assessment using the operation of the micro-energy network over a year as the functional unit and“cradle-to-gate”as the system boundary.Based on the baseline scenario,a natural gas generator set was added to replace central heating,and the light pipes were expanded to constitute the optimized scenario.The results showed that the key impact categories for both scenarios were global warming,fine particulate matter formation,human carcinogenic toxicity,and human non-carcinogenic toxicity.The overall environmental impact of the optimized scenario was reduced by 68%compared to the baseline scenario.A sensitivity analysis of the key factors showed that electricity from the power grid was the key impact factor in both scenarios,followed by central heating and natural gas.Therefore,to reduce the environmental impact of network systems,it is necessary to further optimize the grid power structure.The research approach can be used to optimize micro-energy networks and evaluate the environmental impact of different energy systems.