Autor(es): Ian Vázquez Rowe y otros
Wastewater treatment plants (WWTPs) are regarded as units designed for the efficient removal of organic matter and nutrients from polluted wastewaters, avoiding their discharge into the environment. Despite these benefits, they have also been found to be highly energy intensive, with consequent increased emissions in terms of greenhouse gases and other environmental impacts. Therefore, it has become imperative to monitor thoroughly the overall functioning of WWTPs from an integrated perspective with the aim of understanding how these can improve their eco-efficiency. In this case study, a group of 113 WWTPs located in regions across Spain were analysed using the methodology that combines life cycle assessment (LCA) and data envelopment analysis (DEA). The aim of this work was to determine the operational efficiency of each unit in order to obtain environmental benchmarks for inefficient plants. Thereafter, the environmental gains linked with the inputs reduction proposed for the DEA model for each unit were computed in order to verify eco-efficiency criteria. The operational complexity of WWTPs resulted in several identified factors affecting their efficiency which are discussed in depth, including the size of the facility, the climatic influence, the influent load and the over- or underuse of the plant.
Ir al enlaceAutor(es): Ian Vázquez Rowe y otros
In an international context characterised by the promotion of renewable sources to face an increasing energy demand, grape marc is an organic co-product of the vinification process whose potential as an energy source has been underexploited. This study analysed the production chain of grape marc pellets and evaluated, through an attributional Life Cycle Assessment based on primary data from field experiments, the overall environmental performance of using grape marc pellets for heat production, as well as its comparison with alternative fossil and renewable energy resources. A sensitivity analysis was carried out concerning the type of fuel used for drying, the methodological approach to solve multi-functionality, as well as the influence of the water content of grape marc. The combustion and drying of pellets were found to be the main contributors to the environmental impacts, although a crucial influence of methodological choices on co-products management was observed. The use of wood chips for drying and an optimization of the pellets loading rate in the combustion process are the main improvement recommendations. Overall, results showed that the production of pellets from grape marc for heat production purposes is a promising technology from an environmental perspective, which is always superior to alternative fuels at the endpoint impact level. Compared to fossil fuels, its main advantage lies in the reduced contribution to climate change. When compared to mixed wood chips, it has an advantage regarding the contribution of agricultural land occupation. For policy support purposes, however, this study should be complemented by further analyses focussing, for instance, on market-driven consequences of large scale implementation. The results were shown to be dependent on the midpoint and endpoint impact categories. Their comprehensive interpretation led to the overarching clear recommendation to adapt the impact assessment categories and models and the approach to deal with multi-functionality to the geographical and market specificities features and to assure maximum transparency in the communication of results.
Ir al enlaceAutor(es): Ramzy Kahhat Abedrabbo y otros
Currently, around the globe, environmental and social problems derive from the inappropriate recycling of electronic products. Moreover, improper recycling is not the only issue to address in electronic products. Others include: energy intensity in their manufacture, employment generation related to the international trade in used electronics, and access to technology by low-income communities. Nevertheless, policies and controls created to provide socially and environmentally sound management of used electronics do not match the complexity of the system. In order to understand the e-waste system, particularly used computers, as a whole, a field study was done between 2010 and 2011 in ten Mexican cities. Ninety-five diverse stakeholders were interviewed to uncover factors regarding the decision to waste or trade still-usable computers. Structured analysis was used to create Data Flow Diagrams (DFDs) to describe the critical parts of the system. The results show that perceived value and geographical location determine the rate in which computers are disposed and the opportunities to waste or trade them, including the trade of their materials. Among businesses and other organizations, legislation has a stronger effect. Technological change is another important factor, largely driving the change in materials and new products. Designing policies responding to this diversity may prevent unforeseen problems and stimulate solutions.
Ir al enlaceAutor(es): Isabel Quispe Trinidad y otros
Purpose: Life cycle assessments (LCAs) of various anchovy (anchoveta) direct human consumption products processed in Peru were carried out, to evaluate their relative environmental performance as alternative products to enhance nutrition of communities with low access to fish products in the country. Methods: LCA was carried out for fresh, frozen, canned, salted and cured anchoveta products, both at plant gate and featuring local and national distribution over non-refrigerated, chilled and fully refrigerated distribution chain. The functional unit used was 1 kg of fish in the final product. Results and discussion: Results demonstrate that, in environmental terms, more-refined products (cured and canned anchoveta products) represent a much higher burden than less- refined products (fresh, frozen and salted). Although this is a likely result, the magnitude of this difference (4 to 27 times when expressed as an environmental single score) is higher than expected and had not been quantified before for salted and cured products, as far as we know. This difference is mainly due to differences in energy consumption between types of products. Furthermore, cured and salted products feature larger biotic resource use, when calculated based on the whole fish equivalent, due to higher processing losses/discards. The relevance of taking into account the different transportation and storage needs is highlighted. For those products requiring refrigerated transportation and storage, over a national distribution chain, those activities increase the overall environmental impacts of the products by 55 % (fresh chilled) to 67 % (frozen). However, such an increase does not worsen the environmental performance of fresh and frozen products in comparison to the energy-intensive canned and cured products. Conclusions: It is concluded that a more sustainability-oriented analysis, including the social and economic pillars of sustainability, is required towards decision-making involving promotion of either product for addressing nutritional deficiencies in Peru.
Ir al enlaceAutor(es): Ian Vázquez Rowe y otros
Attributional LCA, which monitors specific production systems in steady state conditions, is increasingly used in fisheries to assess the environmental profile of fleets and seafood supply chains. However, this approach is not pertinent to assess the environmental consequences of (large scale) policies. In contrast, consequential LCA (CLCA) has been successfully implemented in other sectors to assess the expected changes in environmental impacts of a given production system and other (marginal) production systems that may be affected in response to changes driven by policy or strategic decisions. CLCA commonly combines LCA with economic models to simulate the interactions occurring between the analysed systems. However, the use of these models may not be the most appropriate approach to follow for fisheries. Hence, it seems feasible that CLCA should be combined with stock prediction tools rather than with economic models, to determine how changes in stock sizes and quota restrictions may cause variations in the environmental impact of fishing fleets.
Ir al enlaceAutor(es): Ian Vázquez Rowe y otros
The Peruvian anchoveta fishery is currently targeted by a large fleet featuring a wide range of vessel sizes (segments), with highly variable capacities. In addition, the landings of the industrial fleet are used exclusively by the reduction industry, while those performed by small- and medium-scale vessels are destined mainly for direct human consumption. Despite these differences, the entire fleet is made up of purse seiners that perform similar operations when at sea. Therefore, the main aim of this study is to identify the differences in eco-efficiency between the different fleet segments in order to delve into the potential environmental improvements that could be attained through operational benchmarking. To this end, the combined use of Life Cycle Assessment (LCA) and Data Envelopment Analysis (DEA) was applied to the Peruvian anchoveta fleet. More specifically, a modified 5-step LCA + DEA method, whose particularities are broadly discussed throughout the study, was computed to obtain the desired operational benchmarks and, thereafter, estimate the target environmental gains. Results led to an average efficiency score of 86% throughout the segments, with a total of eight fleet segments out of 13 (62%) operating inefficiently. Nevertheless, no clear pattern was identified through the segments, although certain correlations with stock abundance, fuel use intensity, overcapacity and climatic conditions are discussed. Reduction in material inputs based on operational benchmarks translated into environmental gains that ranged from 26% to 53% for inefficient segments. Finally, it is expected that the findings in this study may aid stakeholders and policy makers when revising fuel use optimisation and overcapacity management strategies.
Ir al enlaceAutor(es): Ian Vázquez Rowe y otros
Wine production is an important economic sector in many countries worldwide. In addition, its sales and consumption are steadily augmenting on an annual basis. This has increased the interest by stakeholders and consumers in the environmental sustainability of wine production practices. Despite the wide range of environmental dimensions that are monitored through environmental management tools, worldwide concerns related to greenhouse gas emissions and their effect on global warming have boosted the analysis of a single score indicator to monitor these emissions: carbon footprint (CF). In fact, due to the important consequences that climate change is expected to have on wine appellations and regions, CF has proliferated in this sector in recent years. The aim of this study is to provide a critical review on the application of CF to the wine sector based on peer-reviewed publications, focusing on the controversial methodological assumptions and the level of granularity of the life cycle inventory. Finally, a series of potential advancements in the application of CF to the wine sector will be assessed and discussed.
Ir al enlaceAutor(es): Ian Vázquez Rowe y otros
Viticulture is currently experiencing a gradual shift to more sustainable production practices. Many producers see in this shift an opportunity to increase their sales, especially in a context which is greatly influenced by the reduction in wine sales due to the world economic crisis. Hence, both organic and biodynamic viticulture have begun to be applied in many vineyards as alternative attractive agricultural techniques. Nevertheless, it remains unclear which are the exact environmental benefits (or drawbacks) of applying these techniques for numerous environmental impacts, such as climate change or toxicity. Therefore, the main goal of this study is to perform an environmental evaluation using Life Cycle Assessment (LCA) for three different viticulture techniques within a single appellation (Ribeiro, NW Spain): biodynamic cultivation sites, conventional vineyards and an intermediate biodynamic-conventional wine-growing plantation (i.e. biodynamic site lacking certification). Moreover, two methodological improvements in the field of wine LCA studies are suggested and developed in terms of land use impact categories and labour inclusion in life-cycle thinking. Results demonstrate that biodynamic production implies the lowest environmental burdens, and the highest environmental impacts were linked to conventional agricultural practices. The main reasons for this strong decrease in environmental impacts for the biodynamic site is related to an 80% decrease in diesel inputs, due to a lower application of plant protection products and fertilisers, and the introduction of manual work rather than mechanised activities in the vineyards. Nevertheless, a series of preliminary assessments suggest that the impacts linked to land use and human labour, two under-analysed issues in wine LCA, may show different trends to those obtained for the other environmental dimensions, adding complexity to the integrated interpretation of the results.
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