Inclusion of uncertainty in the LCA comparison of different cherry tomato production scenarios

Purpose

Knowledge regarding environmental impacts of agricultural systems is required. Consideration of uncertainty in life cycle assessment (LCA) provides additional scientific information for decision making. The aims of this study were to compare the environmental impacts of different growing cherry tomato cultivation scenarios under Mediterranean conditions and to assess the uncertainty associated to the different agricultural production scenarios.

Materials and methods

The burdens associated to cherry tomato production were calculated and evaluated by the LCA methodology. The functional unit (FU) chosen for this study was the mass unit of 1 t of commercial loose cherry tomatoes. This study included the quantitative uncertainty analysis through Monte Carlo simulation. Three scenarios were considered: greenhouse (GH), screenhouse (SH), and open field (OF). The flows and processes of the product scenario were structured in several sections: structure, auxiliary equipment, fertilizers, crop management, pesticides, and waste management. Six midpoint impact categories were selected for their relevance: climate change, terrestrial acidification, marine eutrophication, metal depletion, and fossil depletion using the impact evaluation method Recipe Midpoint and ecotoxicity using USEtox.

Results and discussion

The structure, auxiliary equipment, and fertilizers produced the largest environmental impacts in cherry tomato production. The greatest impact in these stages was found in the manufacture and drawing of the steel structures, manufacture of perlite, the amount of HDPE plastics used, and the electricity consumed by the irrigation system and the manufacture and application of fertilizers. GH was the cropping scenario with the largest environmental impact in most categories (varying from 18 and 37% higher than SH and OF, respectively, in metal depletion, to 96% higher than SH and OF, in eutrophication). OF showed the highest uncertainty in ecotoxicity, with a bandwidth of 60 CTUe and a probability of 100 and 99.4% to be higher than GH and SH, respectively.

Conclusions

The LCA was used to improve the identification and evaluation of the environmental burdens for cherry tomato production in the Mediterranean area. This study demonstrates the significance of conducting uncertainty analyses for comparative LCAs used in comparative relative product environmental impacts.

     

Modelling the amount of materials to improve inventory datasets of greenhouse infrastructures

Purpose

Previous studies have shown the importance of including agricultural capital goods in environmental assessments. In particular for protected crops, greenhouse structural components may account for nearly 30 % of the total in environmental impact categories such as resource depletion and global warming. The lack of appropriate datasets can make it difficult to include these structural components. The present paper provides a modelling approach for the greenhouse inventory stage to provide better assessments of greenhouse production systems.

Methods

In this study, four main greenhouse structures were assessed: a glass greenhouse, a multi-tunnel greenhouse, a local Mediterranean type known as the parral greenhouse and a low-tunnel greenhouse. After selecting the main materials of the structure, we generated equations to calculate the amount of the main structural materials as a function of the main greenhouse dimensions. We performed a quality assessment of the data used for different greenhouse structures. We also calculated a simplified environmental assessment made by the different structures to the climate change category in order to test the effects of the different amounts of material in the four greenhouse types.

Results and discussion

Equations to calculate the amount of the main greenhouse materials as a function of greenhouse size are provided. For the four greenhouse types under consideration, statistical correlations showed a good fit between the amounts of greenhouse materials and the parameters related to the main greenhouse dimensions, such as greenhouse perimeter, surface and volume. The results from the complementary impact assessment study show that glass greenhouses contributed the most in the climate change category, with an average value of 2.9 kg CO₂ eq m^?2. After variability was taken into account, multi-tunnel and parral greenhouses showed similar values of between 0.5 and 1.3 kg CO₂ eq m^?2, while low-tunnel greenhouses had the lowest ranges, between 0.4 and 0.6 kg CO₂ eq m^?2. The environmental assessment was done using the square metre as a reference flow, so the actual impact depends on the functional unit selected, which is usually the yield.

Conclusions

Application of the equations developed in this study provides an easy way to calculate the quantity of materials used to make greenhouses of different dimensions, thus resulting in more accurate calculation of greenhouse production system impacts. This analysis also highlights the importance of the different amounts of materials used to build these structures and, therefore, the need to include ranges of uncertainty in environmental analyses.     

Environmental footprint of cooking fuels: a life cycle assessment of ten fuel sources used in Indian households

Purpose

Cooking energy is an essential requirement of any human dwelling. With the recent upsurge in petroleum prices coupled with intrinsic volatility of international oil markets, it is fast turning into a politico-socio-economic dilemma for countries like India to sustain future subsidies on liquefied petroleum gas (LPG) and kerosene. The aim of this paper is to evaluate and compare the environmental performance of various cooking fuel options, namely LPG (NG), LPG (CO), kerosene, coal, electricity, firewood, crop residue, dung cake, charcoal, and biogas, in the Indian context. The purpose of this study is to find environmentally suitable alternatives to LPG and kerosene for rural and urban areas of the country.

Methods

The study assessed the cooking fuel performance on 13 ReCiPe environmental impact categories using the life cycle assessment methodology. The study modeled the system boundary for each fuel based on the Indian scenario and prepared a detailed life cycle inventory for each cooking fuel taking 1 GJ of heat energy transferred to cooking pot as the functional unit.

Results and discussion

The cooking fuels with the lowest life cycle environmental impacts are biogas followed by LPG, kerosene, and charcoal. The environmental impacts of using LPG are about 15 to 18 % lower than kerosene for most environmental impact categories. LPG derived from natural gas has about 20 to 30 % lower environmental impact than LPG derived from crude oil. Coal and dung cake have the highest environmental impacts because of significant contributions to climate change and particulate formation, respectively. Charcoal produced from renewable wood supply performs better than kerosene on most impact categories except photochemical oxidation, where its contribution is 19 times higher than kerosene.

Conclusions

Biogas and charcoal can be viewed as potentially sustainable cooking fuel options in the Indian context because of their environmental benefits and other associated co-benefits such as land farming, local employment opportunities, and skill development. The study concluded that kerosene, biogas, and charcoal for rural areas and LPG, kerosene, and biogas for urban areas have the lower environmental footprint among the chosen household cooking fuels in the study.     

Comparative LCA of ethanol versus gasoline in Brazil using different LCIA methods

Purpose

The main objective of this study is to expand the discussion about how, and to what extent, the environmental performance is affected by the use of different life cycle impact assessment (LCIA) illustrated by the case study of the comparison between environmental impacts of gasoline and ethanol form sugarcane in Brazil.

Methods

The following LCIA methods have been considered in the evaluation: CML 2001, Impact 2002+, EDIP 2003, Eco-indicator 99, TRACI 2, ReCiPe, and Ecological Scarcity 2006. Energy allocation was used to split the environmental burdens between ethanol and surplus electricity generated at the sugarcane mill. The phases of feedstock and (bio)fuel production, distribution, and use are included in system boundaries.

Results and discussion

At the midpoint level, comparison of different LCIA methods showed that ethanol presents lower impacts than gasoline in important categories such as global warming, fossil depletion, and ozone layer depletion. However, ethanol presents higher impacts in acidification, eutrophication, photochemical oxidation, and agricultural land use categories. Regarding to single-score indicators, ethanol presented better performance than gasoline using ReCiPe Endpoint LCIA method. Using IMPACT 2002+, Eco-indicator 99, and Ecological Scarcity 2006, higher scores are verified for ethanol, mainly due to the impacts related to particulate emissions and land use impacts.

Conclusions

Although there is a relative agreement on the results regarding equivalent environmental impact categories using different LCIA methods at midpoint level, when single-score indicators are considered, use of different LCIA methods lead to different conclusions. Single-score results also limit the interpretability at endpoint level, as a consequence of small contributions of relevant environmental impact categories weighted in a single-score indicator.     

Life cycle assessment of fuel ethanol from sugarcane in Argentina

Purpose

The production of bioethanol in Argentina is based on the sugarcane plantation system, with extensive use of agricultural land, scarce use of fertilizers, pesticides, and artificial irrigation, and burning of sugarcane prior to harvesting. The objective of this paper is to develop a life cycle assessment (LCA) of the fuel ethanol from sugarcane in Tucumán (Argentina), assessing the environmental impact potentials to identify which of them cause the main impacts.

Methods

Our approach innovatively combined knowledge about the main impact pathways of bioethanol production with LCA which covers the typical emission-related impact categories at the midpoint life cycle impact assessment. Real data from the Argentinean industry subsystems have been used to perform the study: S1—sugarcane production, S2—milling process, S3—sugar production, and S4—ethanol production from molasses, honey, or sugarcane juice.

Results and discussion

The results are shown in the three alternative pathways to produce bioethanol. Different impact categories are assessed, with global warming potential (GWP) having the highest impact. So, the production of 1 kg of ethanol from molasses emitted 22.5 kg CO₂ (pathway 1), 19.2 kg CO₂ from honey (pathway 2), and 15.0 kg CO₂ from sugarcane juice (pathway 3). Several sensitivity analyses to study the variability of the GWP according to the different cases studied have been performed (changing the agricultural yield, including economic and calorific allocation in sugar production, and modifying the sugar price).

Conclusions

Agriculture is the subsystem which shows the highest impact in almost all the categories due to fossil fuel consumption. When an economic and calorific allocation is considered to assess the environmental impact, the value is lower than when mass allocation is used because ethanol is relatively cheaper than sugars and it has higher calorific value.     

Using a crop model to account for the effects of local factors on the LCA of sugar beet ethanol in Picardy region, France

Purpose

The results of published Life Cycle Assessments (LCAs) of biofuels are characterized by a large variability, arising from the diversity of both biofuel chains and the methodologies used to estimate inventory data. Here, we suggest that the best option to maximize the accuracy of biofuel LCA is to produce local results taking into account the local soil, climatic and agricultural management factors.

Methods

We focused on a case study involving the production of first-generation ethanol from sugar beet in the Picardy region in Northern France. To account for local factors, we first defined three climatic patterns according to rainfall from a 20-year series of weather data. We subsequently defined two crop rotations with sugar beet as a break crop, corresponding to current practice and an optimized management scenario, respectively. The six combinations of climate types and rotations were run with the process-based model CERES-EGC to estimate crop yields and environmental emissions. We completed the data inventory and compiled the impact assessments using Simapro v.7.1 and Ecoinvent database v2.0.

Results

Overall, sugar beet ethanol had lower impacts than gasoline for the abiotic depletion, global warming, ozone layer depletion and photochemical oxidation categories. In particular, it emitted between 28 % and 42 % less greenhouse gases than gasoline. Conversely, sugar beet ethanol had higher impacts than gasoline for acidification and eutrophication due to losses of reactive nitrogen in the arable field. Thus, LCA results were highly sensitive to changes in local conditions and management factors. As a result, an average impact figures for a given biofuel chain at regional or national scales may only be indicative within a large uncertainty band.

Conclusions

Although the crop model made it possible to take local factors into account in the life-cycle inventory, best management practices that achieved high yields while reducing environmental impacts could not be identified. Further modelling developments are necessary to better account for the effects of management practices, in particular regarding the benefits of fertiliser incorporation into the topsoil in terms of nitrogen losses abatement. Supplementary data and modelling developments also are needed to better estimate the emissions of pesticides and heavy metals in the field.     

IMPACT 2002+, ReCiPe 2008 and ILCD’s recommended practice for characterization modelling in life cycle impact assessment: a case study-based comparison

Purpose

The European Commission has launched a recommended set of characterization models and factors for application in life cycle impact assessment (LCIA). However, it is not known how this recommended practice, referred to as the ILCD 2009, performs relative to some of the most frequently used alternative LCIA methodologies. Here, we compare the ILCD 2009 with IMPACT 2002+ and ReCiPe 2008, focusing on characterization at midpoint based on a case study comparing four window design options for use in a residential building.

Methods

Ranking of the four window options was done for each impact category within each methodology. To allow comparison across the methodologies both in terms of total impact scores and contribution patterns for individual substances, impact scores were converted into common metrics for each impact category.

Results and discussion

Apart from toxic impacts on human health and ecosystems, all studied methodologies consistently identify the same window option as having the lowest and the highest environmental impact. This is mainly because few processes, associated with production of heat, dominate the total impacts, and there is a large difference in demand for heat between the compared options. Despite this general agreement in ranking, differences in impact scores are above 3 orders of magnitude for human health impacts from ionizing radiation and ecosystem impacts from land use, and they lie between 1 and 3 orders of magnitude for metal depletion and for toxicity-related impact categories. The differences are somewhat smaller (within 1 order of magnitude) for the impact categories respiratory inorganics and photochemical ozone formation, and are within a factor of 3 for the remaining impact categories. The differences in impact scores in our case study are brought about by the differences in underlying characterization models and/or substance coverage, depending on the impact category.

Conclusions

In spite of substantial differences in impact scores for the individual impact categories, we find that the studied LCIA methods point to the same conclusion with respect to identifying the alternative with the lowest environmental burden and ascribe this to the fact that few processes are driving the main environmental impacts, and there is large difference in demand for output from these processes between the compared options. Even though the overall conclusions remain the same for our case study, the choice of the ILCD’s recommended practice over the existing alternatives does matter for the impact categories ionizing radiation and land use and all toxicity-related impact categories.     

Life cycle assessment of a waste lubricant oil management system

Purpose

This paper compares 16 waste lubricant oil (WLO) systems (15 management alternatives and a system in use in Portugal) using a life cycle assessment (LCA). The alternatives tested use various mild processing techniques and recovery options: recycling during expanded clay production, recycling and electric energy production, re-refining, energy recovery during cement production, and energy recovery during expanded clay production.

Methods

The proposed 15 alternatives and the actual present day situation were analyzed using LCA software UMBERTO 5.5, applied to eight environmental impact categories. The LCA included an expansion system to accommodate co-products.

Results

The results show that mild processing with low liquid gas fuel consumption and re-refining is the best option to manage WLO with regard to abiotic depletion, eutrophication, global warming, and human toxicity environmental impacts. A further environmental option is to treat the WLO using the same mild processing technique, but then send it to expanded clay recycling to be used as a fuel in expanded clay production, as this is the best option regarding freshwater sedimental ecotoxicity, freshwater aquatic ecotoxicity, and acidification.

Conclusions

It is recommended that there is a shift away from recycling and electric energy production. Although sensitivity analysis shows re-refining and energy recovery in expanded clay production are sensitive to unit location and substituted products emission factors, the LCA analysis as a whole shows that both options are good recovery options; re-refining is the preferable option because it is closer to the New Waste Framework Directive waste hierarchy principle.     

Life cycle assessment of medium density particleboard (MDP) produced in Brazil

Purpose

The wood panel industry is one of the most important forest-based industries in Brazil. The medium density particleboard (MDP) is currently produced and consumed worldwide and represents about 50 % of the wood panel industry in Brazil. Unlike other regions, Brazilian MDP is produced from dedicated eucalyptus plantations and heavy fuel oil is an important energy source in MDP manufacture, which may result in a different environmental profile. This paper presents a life cycle assessment of MDP panel produced in Brazil and suggests improvement opportunities by assessing alternative production scenarios.

Methods

The cradle-to-gate assessment of 1 m³ of MDP produced in Brazil considered two main subsystems: forest and industrial production. Detailed inventories for Brazilian eucalyptus production and MDP industrial production were collected as a result of technical visits to Brazilian MDP producers (foreground systems) as well as literature review (mainly background systems). The potential environmental impacts of MDP were assessed in terms of seven impact categories using CML (abiotic depletion, acidification, global warming, eutrophication, and photochemical oxidation) and USEtox (ecotoxicity and human toxicity) impact assessment methods in order to identify the main hotspots.

Results and discussion

The industrial production was responsible for most of the impacts in all impact categories, except ecotoxicity (EC). The main hotspots identified were the use of heavy fuel oil (HFO) as a thermal energy source in MDP manufacture and the production of urea–formaldehyde (UF) resin used as synthetic adhesive. Glyphosate herbicide application in soil in forestry operations was the main responsible for the impacts in EC. Scenarios for HFO substitution were assessed and results showed that substituting HFO for in-mill wood residues or diesel leads to reduced environmental impacts.

Conclusions

The identification of the main hotspots in the MDP life cycle can assist the wood panel industry to improve their environmental profile. Further research should focus on UF resin production in order to reduce its environmental impacts as well as the possibility of using alternatives resins. Other sources of wood for MDP production could also be investigated (e.g., pine wood and wood residues) to assess potential improvements.     

Life cycle assessment of potential energy uses for short rotation willow biomass in Sweden

Purpose

Two different bioenergy systems using willow chips as raw material has been assessed in detail applying life cycle assessment (LCA) methodology to compare its environmental profile with conventional alternatives based on fossil fuels and demonstrate the potential of this biomass as a lignocellulosic energy source.

Methods

Short rotation forest willow plantations dedicated to biomass chips production for energy purposes and located in Southern Sweden were considered as the agricultural case study. The bioenergy systems under assessment were based on the production and use of willow-based ethanol in a flexi fuel vehicle blended with gasoline (85 % ethanol by volume) and the direct combustion of willow chips in an industrial furnace in order to produce heat for end users. The standard framework for LCA from the International Standards Organisation was followed in this study. The environmental profiles as well as the hot spots all through the life cycles were identified.

Results and discussion

According to the results, Swedish willow biomass production is energetically efficient, and the destination of this biomass for energy purposes (independently the sort of energy) presents environmental benefits, specifically in terms of avoided greenhouse gases emissions and fossil fuels depletion. Several processes from the agricultural activities were identified as hot spots, and special considerations should be paid on them due to their contribution to the environmental impact categories under analysis. This was the case for the production and use of the nitrogen-based fertilizer, as well as the diesel used in agricultural machineries.

Conclusions

Special attention should be paid on diffuse emissions from the ethanol production plant as well as on the control system of the combustion emissions from the boiler.     

LCA of a newsprint paper machine: a case study of capital equipment

Purpose

The environmental aspects of paper as a consumer good have been extensively studied. However, the paper machine has been mostly neglected in the literature. The purpose of this article is to present a LCA case study that explicitly focuses on the system of a newsprint paper machine and its environmental impacts and not on the system of the consumer good paper. The relevance of the paper machine as capital equipment is analyzed, and conclusions for the environmental improvement of paper machines are drawn based on identified hotspots. The article hereby answers the more general research questions of whether capital equipment has rightly been neglected in other studies regarding pulp and paper and which impact categories are important for analyzing the environmental burdens of a paper machine.

Methods

The study has been executed in collaboration with Voith Paper, an original equipment manufacturer. Hence, in distinction to literature-based studies, primary data on the paper machine was available resulting in a high overall data quality. Based on the ISO 14040 (2006) and 14044 (2006) standards, this article pursues a cradle-to-grave approach for the paper machine. It assesses the environmental impacts in the impact categories defined by the ReCiPe impact assessment methodology. Different types of energy generation are examined in a scenario analysis with combined heat and power generation (CHP) as the baseline case. For interpretation, a normalization and a sectoral analysis are performed.

Results and discussion

The normalized results indicate fossil resource depletion and global warming as the most important impact categories. Global warming impacts are highly dependent on the energy processes and result to 432.7 kg CO2e per production of 1 t of paper for CHP and to 701.7 kg CO2e for EU25 grid mix. The sectoral analysis shows that the machinery's operations/use phase is clearly dominating most impact categories due to its long lifetime. An exception is the metal depletion, for which the materials and manufacturing processes are most important.

Conclusions

These findings prove that for most categories, the operations/use phase of the paper machine is the most important life cycle stage. In systems focusing on the consumer good paper, it is therefore sufficient to model the operation of the paper machine, whereas the manufacturing, transport, and end-of-life processes regarding the paper machine equipment can be neglected, unless metal depletion is important to the study.     

The influence of contaminants in the environmental impact of recovered paper: a life cycle assessment perspective

Purpose

This study aims to analyze and quantify the environmental impacts associated with the production of testliner paper using 100?% recovered paper as fiber raw material, by applying the life cycle assessment principles. A simulation of advanced sorting technology was done to prepare and use batches of raw materials with different levels of contaminants. Comparative studies of environmental impact assessment were focused on the quality of recovered paper, which is decisively influenced by the efficiency of the sorting process. The particularity of the study is that so far it is the only one that analyzes the environmental impact generated by recovered paper quality.

Methods

To analyze the environmental impacts in the scenarios, life cycle assessment methodology was considered. Potential environmental impacts were assessed by using the CML 2009, Dec.07 method developed by the Centre for Environmental Science from the University of Leiden.

Results and discussion

In this study, acidification potential, abiotic resources depletion potential, eutrophication potential, global warming potential, photochemical ozone creation potential, and human toxicity potential were the impact categories analyzed. Considering that the system boundaries refer only to the paper mill that was obtained, all unitary processes involved in the manufacturing of product system influence in varying proportions the impact categories chosen for evaluation. A higher concentration of contaminants leads to a higher amount of energy and water used, and thus, a significant amount of waste and emissions generated. Simulations performed have highlighted the importance of sorting technology that influences the quality of raw material that will be used.

Conclusions

Utilization of recovered paper batches with a low quality contributes to an increased environmental impact associated with the testliner paper manufacturing stage. A low quality of recovered paper will influence energy consumption in different modules of the system (recycled fiber pulp preparation, paper machine, and wastewater treatment), the volume of waste generated, and consequently the emissions released both in air and water.     

Integrating triple bottom line input–output analysis into life cycle sustainability assessment framework: the case for US buildings

Purpose

With the increasing concerns related to integration of social and economic dimensions of the sustainability into life cycle assessment (LCA), traditional LCA approach has been transformed into a new concept, which is called as life cycle sustainability assessment (LCSA). This study aims to contribute the existing LCSA framework by integrating several social and economic indicators to demonstrate the usefulness of input–output modeling on quantifying sustainability impacts. Additionally, inclusion of all indirect supply chain-related impacts provides an economy-wide analysis and a macro-level LCSA. Current research also aims to identify and outline economic, social, and environmental impacts, termed as triple bottom line (TBL), of the US residential and commercial buildings encompassing building construction, operation, and disposal phases.

Methods

To achieve this goal, TBL economic input–output based hybrid LCA model is utilized for assessing building sustainability of the US residential and commercial buildings. Residential buildings include single and multi-family structures, while medical buildings, hospitals, special care buildings, office buildings, including financial buildings, multi-merchandise shopping, beverage and food establishments, warehouses, and other commercial structures are classified as commercial buildings according to the US Department of Commerce. In this analysis, 16 macro-level sustainability assessment indicators were chosen and divided into three main categories, namely environmental, social, and economic indicators.

Results and discussion

Analysis results revealed that construction phase, electricity use, and commuting played a crucial role in much of the sustainability impact categories. The electricity use was the most dominant component of the environmental impacts with more than 50 % of greenhouse gas emissions and energy consumption through all life cycle stages of the US buildings. In addition, construction phase has the largest share in income category with 60 % of the total income generated through residential building’s life cycle. Residential buildings have higher shares in all of the sustainability impact categories due to their relatively higher economic activity and different supply chain characteristics.

Conclusions

This paper is an important attempt toward integrating the TBL perspective into LCSA framework. Policymakers can benefit from such approach and quantify macro-level environmental, economic, and social impacts of their policy implications simultaneously. Another important outcome of this study is that focusing only environmental impacts may misguide decision-makers and compromise social and economic benefits while trying to reduce environmental impacts. Hence, instead of focusing on environmental impacts only, this study filled the gap about analyzing sustainability impacts of buildings from a holistic perspective.     

Environmental life cycle assessment of a dairy product: the yoghurt

Purpose

The dairy sector covers multiple activities related to milk production and treatment for alimentary uses. Different dairy products are available in the markets, with yoghurt being the second most important in terms of production. The goal of this study was to analyse from a cradle-to-grave approach the environmental impacts and energy balance derived from the yoghurt (solid, stirred and drinking yoghurts) manufacture process in a specific dairy factory processing 100 % Portuguese raw milk.

Methods

The standard framework of life cycle assessment (LCA) was followed and inventory data were collected on site in the dairy factory and completed using the literature and databases. The following impact categories were evaluated adopting a CML method: abiotic depletion (ADP), acidification (AP), eutrophication (EP), global warming (GWP), ozone layer depletion (ODP), land competition (LC) and photochemical oxidants formation (POFP), with the energy analysis carried out based on the cumulative non-renewable fossil and nuclear energy demand (CED). A mass allocation approach was considered for the partitioning of the environmental burdens between the different products obtained since not only yoghurts are produced but also dairy fodder.

Results and discussion

The key processes from an environmental point of view were identified. Some of the potential results obtained were in line with other specific related studies where dairy systems were assessed from an LCA perspective. The production of the milk-based inputs (i.e. raw milk, concentrated and powdered milk) was the main factor responsible of the environmental loads and energy requirements, with remarkable contributions of 91 % of AP, 92 % of EP and 62 % of GWP. Other activities that have important environmental impacts include the production of the energy requirements in the dairy factory, packaging materials production and retailing. Potential alternatives were proposed in order to reduce the contributions to the environmental profile throughout the life cycle of the yoghurt. These alternatives were based on the minimisation of milk losses, reductions of distances travelled and energy consumption at retailing and household use, as well as changes to the formulation of the animal feed. All of these factors derived from light environmental reductions.

Conclusions

The main reductions of the environmental impact derived from yoghurt production can be primarily obtained at dairy farms, although important improvements could also be made at the dairy factory.     

Environmental and energy assessment of the substitution of chemical fertilizers for industrial wastes of ethanol production in sugarcane cultivation in Brazil

Purpose

Vinasse and filter cake are residues of bioethanol processing that are used to be recycled as fertilizers in sugarcane plantation. Studies related to the environmental dimension on this practice are concerned only with the effects on water and soil. The present study examines the systemic effects of replacing chemical fertilizers with vinasse and filter cake on the environmental performance of ethanol, via life cycle assessment (LCA).

Methods

The analysis was carried out by comparing various scenarios structured from two control variables: crop management techniques (manual and mechanized harvesting) and source of nutrients (for supplying the nutritional needs of sugarcane crops): chemical fertilizers, chemical fertilizers + vinasse, and chemical fertilizer + vinasse + filter cake. Impact assessment was carried out in terms of primary energy demand, climate change, terrestrial acidification, freshwater eutrophication, human toxicity, and terrestrial ecotoxicity. LCA has been applied according to both attributional and consequential perspectives. Moreover, a sensitivity analysis was performed in order to verify the effects of the varying amounts of nitrogen (N), phosphorus (P), and potassium (K) in the composition of vinasse on the results obtained for the impact profile.

Results and discussion

From the attributional LCA perspective, the most expressive contributions regarding primary energy demand occurred in terms of depletion of non-renewable fossils. Replacing chemical fertilizers with vinasse and filter cake was beneficial for the environmental performance of ethanol as it reduces climate change, terrestrial acidification, and human toxicity impacts and sustains freshwater eutrophication and terrestrial ecotoxicity unaltered in relation to scenarios using only fertilizers. In terms of consequential LCA, ethanol’s environmental performance is influenced by the inclusion of the production of calcium fluorite to compensate the hexafluorosilicic acid deficit occurring in conjunction to the decrease of phosphate fertilizer and is compensated by the benefits provided by the general reduced consumption of chemical fertilizers for most of the impact categories. The exception occurred for primary energy demand.

Conclusions

The reuse of residues from bioethanol production—vinasse and filter cake—as primary nutrient suppliers for the cultivation of sugarcane instead of chemical fertilizers is a valid practice that improves the environmental performance of ethanol, even if it is analyzed under a consequential LCA perspective. The transport of these inputs to the field must be managed, however, in order to minimize primary energy demand and climate change impacts.

     

Life cycle assessment of a biobased chainsaw oil made on the farm in Wallonia

Purpose

The environmental issue is a particular concern for chainsaw oils because these fluids represent a total loss system. The aim of this study is to quantify the environmental impacts of a biobased chainsaw oil made on the farm in Wallonia (a region of Belgium) and to compare it with a model mineral chainsaw oil. With this study, the aim is also to participate in the development of the life cycle assessment (LCA) methodology applied to the biolubricant sector since LCAs on these products are quite limited and rarely sufficiently detailed.

Method

In this LCA, the attributional approach is applied. Seven impact categories are studied. The methods for life cycle impact assessment are IPCC, ReCiPe, CML and USEtox. The functional unit is 1 kg of base oil. Seven sensitivity analyses are performed.

Results and discussion

Results indicate that the biobased chainsaw oil made on the farm has a lower impact for the global warming potential, the abiotic depletion potential, the ozone depletion potential and the photochemical oxidation potential. On the contrary, it has larger acidification, aquatic eutrophication and aquatic ecotoxicity potential impacts. Regarding the contribution of the life cycle stages of the biobased chainsaw oil, the agricultural stage causes the highest contribution in all impact categories. For the mineral chainsaw oil, the refining stage is preponderant for all impact categories except for the global warming potential for which the end-of-life stage contributes the most. When taking additives into account, conclusions regarding the comparison between the oils are not reversed. Even if it was necessary to consume more biobased than mineral chainsaw oil, conclusions regarding the comparison of the oils would not be reversed. In the same way, a different allocation procedure for rapeseed oil and rape meal, a different rape seeds yield or different extraction yields in the refining stage of the mineral base oil do not change the results of the comparison. For the biobased chainsaw oil, the substitution of only one active substance in the agricultural stage could result in an important decrease of the freshwater ecotoxicity impact.

Conclusions

The biobased chainsaw oil has a lower impact in four out of the seven impact categories and a higher impact in three impact categories. By providing a detailed LCA on a biobased chainsaw oil, this study contributes to the development of LCA applied to biobased lubricants.     

A life cycle assessment study of a Canadian post-combustion carbon dioxide capture process system

Purpose

While carbon dioxide capture and storage (CCS) has been widely recognized as a useful technology for mitigating greenhouse gas emissions, it is necessary to evaluate the environmental performance of CCS from a full life cycle perspective to comprehensively understand its environmental impacts. The primary research objective is to conduct a study on life cycle assessment of the post-combustion carbon dioxide capture process based on data from SaskPower’s electricity generation station at the Boundary Dam in Saskatchewan, Canada. A secondary objective of this study is to identify the life cycle impact assessment (LCIA) methodology which is most suitable for the assessment of carbon dioxide capture technology integrated with the power generation system in the Canadian context.

Methods

The study takes a comparative approach by including three scenarios of carbon dioxide capture at the electricity generation station: no carbon dioxide capture (“no capture”), partial capture (“retrofit”), and fully integrated carbon dioxide capture of the entire facility (“capture”). The four LCIA methods of EDIP 97, CML2001, IMPACT2002+, and TRACI are used to convert existing inventory data into environmental impacts. The LCIA results from the four methods are compared and interpreted based on midpoint categories.

Results and discussion

The LCA results showed an increase in the retrofit and capture scenarios compared to the no capture scenario in the impact categories of eutrophication air, ecotoxicity water, ecotoxicity ground surface soil, eutrophication water, human health cancer ground surface soil, human health cancer water, human health noncancer ground surface soil, ozone depletion air, human health noncancer water, and ionizing radiation. The reductions were observed in the retrofit and capture scenarios in the impact categories of acidification, human health criteria air-point source, human health noncancer air, ecotoxicity air, global warming, human health cancer air, and respiratory effects.

Conclusions

Although the four LCIA methodologies significantly differ in terms of reference substances used for individual impact categories, all (TRACI, IMPACT2002+, CML2001, and EDIP 97) showed similar results in all impact categories.     

Comparative life cycle assessment of reused versus disposable dental burs

Purpose

Health care infection control has led to increased utilization of disposable medical devices, which has subsequently led to adverse environmental effects attributed to health care and its supply chain. In dental practice, the dental bur is a commonly used instrument that can be either reused or used once and then disposed. To evaluate the disparities in environmental impacts of disposable and reusable dental burs, a comparative life cycle assessment (LCA) was performed.

Methods

The functional unit was defined as one reusable dental bur, where the maximum instances reused was 30 (or in the case of a disposable, the equivalent functional unit would be 30 disposable dental burs). The system boundary included all cradle-to-grave aspects of both single-use and reused burs, including raw material extraction, manufacturing, packaging, distribution, reuse, and disposal. Primary data included the following: operating parameters for ultrasonic cleaning, manual cleaning, and autoclaving of the burs. The secondary data for raw material extraction and production of dental bur and packaging were obtained directly from life cycle inventory databases. Sensitivity analyses were also performed with respect to ultrasonic and autoclave loading.

Results and discussion

Findings from this research showed that when the ultrasonic and autoclave were loaded optimally, reusable burs had 40 % less of an environmental impact than burs used on a disposable basis. When the autoclave and ultrasonic were loaded to approximately two-third capacity, four environmental impact categories favored reusable burs (i.e., ozone depletion, smog, respiratory effects, exotoxicity), and four impact categories environmentally favored disposables (i.e., acidification, eutrophication, carcinogenics, and non-carcinogenics). When the autoclave and ultrasonic were loaded to approximately one-third capacity, reusable dental burs posed more negative environmental impacts in eight of nine environmental impact categories when compared to disposable burs.

Conclusions

Operational efficiency of ultrasonic and autoclave cleaning equipment should be emphasized to enhance the environmental performance of bur reuse. In fact, improper loading of the ultrasonic and autoclave can lead to greater adverse environmental impacts than if the burs were treated as disposables. The environmental and economic impacts associated with bur reuse are expected to be similar with other dental devices that are designated as disposable but are capable of being reused (e.g., scalpels, forceps).     

A life cycle assessment of packaging options for contrast media delivery: comparing polymer bottle vs. glass bottle

Purpose

This paper compares environmental impacts of two packaging options for contrast media offered by GE Healthcare: +PLUSPAK? polymer bottle and traditional glass bottle. The study includes all relevant life cycle stages from manufacturing to use and final disposal of the bottles and includes evaluation of a variety of end-of-life disposal scenarios. The study was performed in accordance with the international standards ISO 14040/14044, and a third-party critical review was conducted.

Methods

The functional unit is defined as the packaging of contrast media required to deliver one dose of 96 mL to a patient for an X-ray procedure. Primary data are from GE Healthcare and its suppliers; secondary data are from the ecoinvent database and the literature. A variety of end-of-life disposal scenarios are explored using both cutoff and market-based allocation. Impact assessment includes human health (midpoint) and ecosystems and resources (end point) categories from ReCiPe (H) and cumulative energy demand. Sensitivity analyses include (1) bottle size, (2) secondary packaging, (3) manufacturing electricity, (4) glass recycled content, (5) scrap rate, (6) distribution transport, (7) contrast media, and (8) choice of impact assessment method. Uncertainty analysis is performed to determine how data quality affects the study conclusions.

Results and discussion

This study indicates that the polymer bottle outperforms the glass bottle in every environmental impact category considered. Bottle components are the most significant contributors, and the vial body has the highest impacts among bottle components for both polymer and glass bottles. The polymer bottle exhibits lower impact in all impact categories considered regardless of the following: end-of-life treatment (using either cutoff or market-based allocation), bottle size, manufacturing electricity grid mix, glass recycled content, scrap rate, contrast media, distribution transport (air vs. ocean), and choice of impact assessment method. Secondary packaging can be a major contributor to impact. The polymer bottle has considerably lower impact compared to the glass bottle for all multi-pack configurations, but the comparison is less clear for single-pack configurations due to significantly higher packaging material used per functional dose, resulting in proportionally higher impacts in all impact categories.

Conclusions

The lower impacts of the polymer bottle for this packaging application can be attributed to lower material and manufacturing impacts, lower distribution impacts, and lower end-of-life disposal impacts. The results of this study suggest that using polymer rather than glass bottles provides a means by which to lower environmental impact of contrast media packaging.