Environmental impact assessment of lignocellulosic lactic acid production: Integrated with existing sugar mills

Lactic acid (LA) is considered for the diversification and value addition to sugar industry in South Africa, through a bioconversion of sugarcane bagasse and leaves. A bioconversion process was modeled in Aspen Plus (R) V8.6 and its environmental impacts were evaluated using the Life Cycle Assessment method using SimaPro (R) considering its integration into existing South African Sugar mills. The life cycle approach took into account the whole sugar production chain, including sugarcane cultivation stage, harvesting and transportation of sugarcane, sugar mill, and LA production. The life cycle inventories of the sugarcane cultivation and sugar mill were obtained from literature while Aspen Plus (R) simulation data were used for the LA production. The ecoinvent database of SimaPro (R) was used for all external inputs and fossil-based LA production. Environmental impacts of the biobased and fossil based LA productions were assessed and compared. The total environmental savings of the major impact categories obtained upon replacing a tonne of fossil-based LA with biobased LA are: 3925.65 kg CO2 eq. of global warming potential; 1742.05 kg fossil fuel eq. of abiotic depletion potential; 1296.16 kg 1,4-DB eq. of human toxicity potential; 397.79 kBq U-235 eq. of ionizing radiation potential; 253.97 kg Fe eq. of metal depletion potential; 43.48 kg 1,4-DB eq. of marine aquatic ecotoxicity potential; 42.97 kg 1,4-DB eq. of fresh water aquatic ecotoxicity potential and 18.23 kg SO2 eq. of acidification potential. Auxiliary chemicals used in the biobased LA production are most relevant to the total environmental impacts. Thus, biobased LA production has significantly reduced the impact on the environment, giving 80-99% environmental savings compared to fossil-derived LA. (C) 2016 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

Life Cycle Assessment of Soybean-Based Biodiesel in Argentina for Export

Arnaud Dauriat, Edgard Gnansounou, Luis Alberto Panichelli

Background, aim and scope. Regional specificities are a key factor when analyzing the environmental impact of a biofuel pathway through a life cycle assessment (LCA). Due to different energy mixes, transport distances, agricultural practices and land use changes, results can significantly vary from one country to another. The Republic of Argentina is the first exporter of soybean oil and meal and the third largest soybean producer in the world, and therefore, soybean-based biodiesel production is expected to significantly increase in the near future, mostly for exportation. Moreover, Argentinean biodiesel producers will need to evaluate the environmental performances of their product in order to comply with sustainability criteria being developed. However, because of regional specificities, the environmental performances of this biofuel pathway can be expected to be different from those obtained for other countries and feedstocks previously studied. This work aims at analyzing the environmental impact of soybean-based biodiesel production in Argentina for export. The relevant impact categories account for the primary non-renewable energy consumption (CED), the global warming potential (GWP), the eutrophication potential (EP), the acidification potential (AP), the terrestrial ecotoxicity (TE), the aquatic ecotoxicity (AE), the human toxicity (HT) and land use competition (LU). The paper tackles the feedstock and country specificities in biodiesel production by comparing the results of soybean-based biodiesel in Argentina with other reference cases. Emphasis is put on explaining the factors that contribute most to the final results and the regional specificities that lead to different results for each biodiesel pathway. Materials and methods. The Argentinean (AR) biodiesel pathway was modelled through an LCA and was compared with reference cases available in the ecoinvent® 2.01 database, namely, soybean-based biodiesel production in Brazil (BR) and the United States (US), rapeseed-based biodiesel production in the European Union (EU) and Switzerland (CH) and palm-oil-based biodiesel production in Malaysia (MY). In all cases, the systems were modelled from feedstock production to biodiesel use as B100 in a 28 t truck in CH. Furthermore, biodiesel pathways were compared with fossil low-sulphur diesel produced and used in CH. The LCA was performed according to the ISO standards. The life cycle inventory and the life cycle impact assessment (LCIA) were performed in Excel spreadsheets using the ecoinvent® 2.01 database. The cumulative energy demand (CED) and the GWP were estimated through the CED for fossil and nuclear energy and the IPCC 2001 (climate change) LCIA methods, respectively. Other impact categories were assessed according to CML 2001, as implemented in ecoinvent. As the product is a fuel for transportation (service), the system was defined for one vehicle kilometre (functional unit) and was divided into seven unit processes, namely, agricultural phase, soybean oil extraction and refining, transesterification, transport to port, transport to the destination country border, distribution and utilisation. Results. The Argentinean pathway results in the highest GWP, CED, AE and HT compared with the reference biofuel pathways. Compared with the fossil reference, all impact categories are higher for the AR case, except for the CED. The most significant factor that contributes to the environmental impact in the Argentinean case varies depending on the evaluated category. Land provision through deforestation for soybean cultivation is the most impacting factor of the AR biodiesel pathway for the GWP, the CED and the HT categories. Whilst nitrogen oxide emissions during the fuel use are the main cause of acidification, nitrate leaching during soybean cultivation is the main factor of eutrophication. LU is almost totally affected by arable land occupation for soybean cultivation. Cypermethrin used as pesticide in feedstock production accounts for almost the total impact on TE and AE. Discussion. The sensitivity analysis shows that an increase of 10% in the soybean yield, whilst keeping the same inputs, will reduce the total impact of the system. Avoiding deforestation is the main challenge to improve the environmental performances of soybean-based biodiesel production in AR. If the soybean expansion can be done on marginal and set-aside agricultural land, the negative impact of the system will be significantly reduced. Further implementation of crops’ successions, soybean inoculation, reduced tillage and less toxic pesticides will also improve the environmental performances. Using ethanol as alcohol in the transesterification process could significantly improve the energy balance of the Argentinean pathway. Conclusions. The main explaining factors depend on regional specificities of the system that lead to different results from those obtained in the reference cases. Significantly different results can be obtained depending on the level of detail of the input data, the use of punctual or average data and the assumptions made to build up the LCA inventory. Further improvement of the AR biodiesel pathways should be done in order to comply with international sustainability criteria on biofuel production. Recommendations and perspectives. Due to the influence of land use changes in the final results, more efforts should be made to account for land use changes others than deforestation. More data are needed to determine the part of deforestation attributable to soybean cultivation. More efforts should be done to improve modelling of interaction between variables and previous crops in the agricultural phase, future transesterification technologies and market prices evolution. In order to assess more accurately the environmental impact of soybean-based biodiesel production in Argentina, further considerations should be made to account for indirect land use changes, domestic biodiesel consumption and exportation to other regions, production scale and regional georeferenced differentiation of production systems.

2009

Life cycle environmental assessment of retaining walls in unsaturated soils

Alessio Ferrari, Gianluca Speranza

Retaining structures above groundwater level support soils that are usually in a state of partial saturation and subject to the actions of atmospheric agents. The current design approach considers the possible extremes of soil conditions - either totally dry or totally saturated - but it neglects matric suction's contribution to soil shear strength. This work aims to describe how unsaturated-soil mechanics of can positively influence the sustainability of retaining structures through a holistic, multidisciplinary, geotechnical, and environmental analysis. The geotechnical analysis allows to estimate the lateral earth pressure of a geostructure in both unsaturated and extreme soil conditions (dry or saturated), which will directly influence the geometrical dimensions of the geostructure. Next, the environmental analysis is performed with the standardized and globally applied Life Cycle Assessment (LCA) tool, in order to quantify the potential environmental impacts of the retaining structure according to both a life cycle and a multi-criteria perspective. First, an LCA model is built for a cantilever retaining wall according to two design approaches: (a) an unsaturated design approach (UDA), i.e. when unsaturated soils' principles are considered in the design procedure, and (b) a conventional design approach (CDA), i.e. if soil is considered dry or saturated. Three different types of retained soil (i.e. fine-grained soil, volcanic ash, and coarse-grained soil) are considered. Then, the associated environmental impacts on climate change, human health, ecosystems and resources are calculated for the two design approaches. Their comparison allows to quantify the potential reductions in environmental damages provided by the adoption of unsaturated-soil mechanics. The presented case study shows a high potential reduction in environmental impacts for retaining walls interacting with fine-grained soils (silt), lower potential environmental benefits with volcanic ash (clayey-silty sand), but no environmental gain for interaction with a coarse-grained soil (sand) compared to a conventional design approach considering extreme soil conditions. (c) 2021 Elsevier Ltd. All rights reserved.

ELSEVIER2022

Assessing the life cycle costs and environmental performance of lightweight materials in automobile applications

Christian Ludwig, Jan-Anders Månson, Véronique Michaud, Jérôme Payet, Robert Andrew Witik

Life cycle assessment (LCA) and manufacturing focused life cycle costing are used to evaluate the potential advantages of composites in automotive applications. The life cycle costs and environmental performance of several suitable lightweight polymer composites are quantified and compared against magnesium and steel for a representative component. The results indicate that weight reduction will not always lead to improved environmental performance. Materials offering high weight savings such as carbon fibres and magnesium have been shown to give limited or negative environmental benefits over their life cycles due to increased environmental burdens associated with their production. Lower performance materials such as sheet moulding compounds were found to perform better from a life cycle perspective despite not being recycled. Lighter weight vehicle components were found to be always more costly; however their use did lead to reduced costs for the consumer through lower fuel consumption. (C) 2011 Elsevier Ltd. All rights reserved.