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By means of the life cycle assessment methodology, the purpose of this study is to assess the environmental impact when biomethane from organic waste produced at residential level is used to supply energy to a group of dwellings in the distributed generation paradigm. Three different Combined Heat and Power systems, such as fuel cells, Stirling engine and micro gas turbine, installed at household level are assessed in two different settings: one in Northern Europe (UK) and one in Southern Europe (Italy). Different operating strategies are investigated for each technology. Moreover, marginal electricity production technologies are analysed to assess their influence on the results. This study has demonstrated that the type of bio-methane fed micro-CHP technology employed has a significantly different environmental impact: fuel cells are the most environmentally friendly solution in every category analysed; Stirling engines, although can supply heat to the largest number of dwellings are the least environmentally friendly technology. However, key factors investigated in the model presented in this paper influence the decision making on the type of technology adopted and the operating strategy to be implemented. [ABSTRACT FROM AUTHOR]

Abstract: Producer responsibility and take-back legislation in Europe place responsibility on the manufactures for the recovery and recycling of end-of-life products. This will inevitably require the manufacturers to rethink the way products are designed and manufactured in order to improve their recyclability. This paper illustrates on the case of a fibre optic cable how this can be achieved in a practical and relatively easy way, leading to both environmental and economic benefits. The case study compares the current design the 96 fibre optic cable with several proposed design modifications with the aim of identifying the design option that would enable an easy end-of-life disassembly and recycling of component materials. The designs are evaluated on a life cycle basis for both economic and environmental impacts using the CHAin management of Materials and Products (CHAMP) methodology. CHAMP combines elements of process and design engineering with life cycle approaches to enable the user to explore technical, economic and environmental consequences of different material, process and technological options, including material recovery and recycling. CHAMP is therefore particularly well suited for addressing the requirements of the take-back and producer responsibility legislation. The results of LCA and life cycle costing obtained by using CHAMP show that cable re-design can reduce the environmental impacts by between 30 and 60% and can lead to a 40% reduction in economic costs. This is achieved by changing the internal structure of the cable, by removing some of the cable components (e.g. aluminium and organic gels) and by recycling some of the materials. Transport (including reverse logistics), processing and landfill also contribute to the overall impacts, but their contribution is less significant than that from the materials used to manufacture the cable. [Copyright &y& Elsevier]

Indicators which reflect environmental, economic, health and safety issues, have been categorized as microecometrics and macroecometrics. The former, generally flow based measures, have been developed for local, firm-wide or product based assessments. Microecometrics include materials intensity, energy consumption and emissions data, often from life cycle perspectives. They are, generally, intensive and are scaled with respect to unit of production, GDP or per capita, though other normalization factors have been proposed. In contrast macroecometrics tend to be extensive and represent global conditions such as temperatures and environmental concentrations. Ecometrics are subjective and reflect the dominant value of the individual, family unit, stakeholder group or firm. As such overaggregating or reducing the number of ecometrics for given applications, such as the rating of investments or access to credit, presents potential conflicts. Furthermore, while eco-indicators used for internal corporate reporting should not, necessarily, be validated, those microecometrics which involve external reporting, or multiple stakeholders, are arbitrary if not derived from, or based on, comprehensive life cycle approaches. This paper summarizes ECOMETRICS’98, a workshop held in Lausanne, Switzerland in January 19–20, 1998. It discusses ecometric needs of various users including consumers, designers, private sector decision makers as well as politicians and policy makers. A discussion regarding appropriate microecometrics for industrial sectors including chemical, pharmaceutical, insurance, finance, electronics, manufacturing and consumer products is also summarized. [ABSTRACT FROM AUTHOR]

Activated carbons have excellent performance in a number of process applications. In particular, they appear to have the most favourable characteristics for adsorption processes, thanks to their high porosity and large surface area. However, a comprehensive assessment of the environmental impacts of their manufacturing chain is still lacking. This study evaluates these impacts taking the specific case of activated carbon produced from coconut shells in Indonesia, which is the major coconut producer county. Coconut shells as raw materials are utilized for activated carbon production due to their abundant supply, high density and purity, and because they seem to have a clear environmental advantage over coal-based carbons, particularly in terms of acidification potential, non-renewable energy demand and carbon footprint. Life Cycle Assessment and process analysis are used to quantify all the environmental interactions over the stages of the life cycle of an activated carbon manufacturing chain, in terms of inputs of energy and natural resources and of outputs of emissions to the different environmental compartments. Estimates for the environmental burdens over the life cycle have been obtained by developing mass and energy balances for each of the process units in the production chain. The results indicate the operations with the greatest effects on the environmental performance of activated carbon production and hence where improvements are necessary. In particular, using electrical energy produced from renewable sources, such as biomass, would reduce the contributions to human toxicity (by up to 60%) and global warming (by up to 80%). Moreover, when the material is transported for processing in a country with a low-carbon electricity system, the potential human toxicity and global warming impacts can be reduced by as much as 90% and 60% respectively. [ABSTRACT FROM AUTHOR]

In the past, almost all residual municipal waste in the UK was landfilled without treatment. Recent European waste management directives have promoted the uptake of more sustainable treatment technologies, especially for biodegradable waste. Local authorities have started considering other options for dealing with residual waste. In this study, a life cycle assessment of a future 20 MWe plant using an advanced two-stage gasification and plasma technology is undertaken. This plant can thermally treat waste feedstocks with different composition and heating value to produce electricity, steam and a vitrified product. The objective of the study is to analyse the environmental impacts of the process when fed with seven different feedstocks (including municipal solid waste, solid refuse fuel, reuse-derived fuel, wood biomass and commercial & industrial waste) and identify the process steps which contribute more to the environmental burden. A scenario analysis on key processes, such as oxygen production technology, metal recovery and the appropriate choice for the secondary market aggregate material, is performed. The influence of accounting for the biogenic carbon content in the waste from the calculations of the global warming potential is also shown. Results show that the treatment of the refuse-derived fuel has the lowest impact in terms of both global warming potential and acidification potential because of its high heating value. For all the other impact categories analysed, the two-stage gasification and plasma process shows a negative impact for all the waste streams considered, mainly due to the avoided burdens associated with the production of electricity from the plant. The plasma convertor, key characteristic of the thermal process investigated, although utilising electricity shows a relatively small contribution to the overall environmental impact of the plant. The results do not significantly vary in the scenario analysis. Accounting for biogenic carbon enhanced the performance of biomass and refuse-derived fuel in terms of global warming potential. The main analysis of this study has been performed from a waste management perspective, using 1 ton of waste as functional unit. A comparison of the results when 1 kWhe of electricity produced is used as functional unit shows similar trends for the environmental impact categories considered. [ABSTRACT FROM AUTHOR]

The EU landfill and Waste Framework directives are driving new approaches to waste management in the UK, away from landfilling and mass-burn incineration, which has been regarded as the main alternative to landfilling. The objective of this study is to compare the environmental impacts of three dual-stage advanced energy-from-waste technologies, i.e. gasification and plasma gas cleaning, fast pyrolysis and combustion and gasification with syngas combustion, with those associated with conventional treatments for municipal solid waste, i.e. landfill with electricity production and incineration with electricity production. Results show that the two-stage gasification and plasma process has a significantly better overall environmental performance than the conventional waste treatment technologies and somewhat better than a more modern incineration plant, exemplified by a plant under commissioning in Lincolnshire in the UK. The benefits of the gasification and plasma process arise primarily from its higher net electrical efficiency. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the anticipated environmental benefits from integrating a dairy farm and a greenhouse; the integration is based on anaerobic digestion of manures to produce biogas energy, biogenic CO 2 , and digested slurry. A full Life Cycle Assessment (LCA) has been conducted on six modeled cases applicable in British Columbia, to evaluate non-renewable energy consumption, climate change, acidification, eutrophication, respiratory effects and human toxicity. Compared to conventional practice, an integrated system has the potential to nearly halve eutrophication and respiratory effects caused by inorganic emissions and to reduce non-renewable energy consumption, climate change, and acidification by 65–90%, while respiratory effects caused by organic emissions become negative as co-products substitute for other materials. Co-digestion of other livestock manures, greenhouse plant waste, or food and food processing waste with dairy manure can further improve the performance of the integrated system. [ABSTRACT FROM AUTHOR]

To achieve more than incremental reductions in resource consumption and waste, it will be necessary to develop new approaches to the systematic use and re-use of materials in the kind of system termed an “industrial ecology”. This paper presents a new methodology—CHAin Management of Materials and Products (CHAMP)—developed for modelling the flow of materials through a succession of uses with different performance requirements. Although developed specifically for polymers, the CHAMP approach is also applicable to other materials and products. Materials are characterised by a set of technical performance parameters, termed utilities. Geographical location is also treated as a utility to enable logistics—both distribution of products and collection of used products or waste—to be incorporated within the same modelling framework. Processing, transport and use are treated as activities through which a material can pass. The costs and environmental impacts of activities are included in the modelling framework, and are assessed on a life cycle basis by considering the complete supply chain of materials and energy used by each activity. The methodology includes acceptance criteria which determine whether a material is suitable for specific uses or activities. These criteria are applied within the model to guide selection of materials for specific applications and of successive uses for specific materials. A simple example of the CHAMP approach is given, to illustrate the kinds of problem to which it has been applied. [Copyright &y& Elsevier]

The earlier in the development of a process a design change is made, the lower the cost and the higher the impact on the final performance. This applies equally to environmental and technical performance, but in practice the environmental aspects often receive less attention. To maximise sustainability, it is important to review all of these aspects through each stage, not just after the design. Tools that integrate environmental goals into the design process would enable the design of more environmentally friendly processes at a lower cost. This paper brings together approaches based on Life Cycle Assessment (LCA) including comparisons of design changes, hotspot analysis, identification of key impact categories, environmental break-even analysis, and decision analysis using ternary diagrams that give detailed guidance for design while not requiring high quality data. The tools include hotspot analysis to reveal which unit operations dominate the impacts and therefore should be the focus of further detailed process development. This approach enables the best variants to be identified so that the basic design can be improved to reduce all significant environmental impacts. The tools are illustrated by a case study on the development of a novel process with several variants: thermal cracking of mixed plastic waste to produce a heavy hydrocarbon product that can displace crude oil, naphtha, or refinery wax or be used as a fuel. The results justified continuing with the development by confirming that the novel process is likely to be a better environmental option than landfill or incineration. The general approach embodied in the toolkit should be applicable in the development of any new process, particularly one producing multiple products. [ABSTRACT FROM AUTHOR]

Highlights: [•] We investigated the environmental impact of treatment of OFMSW in London. [•] We performed LCA with sensitivity analysis to test the robustness of the model. [•] We found AD is the best option for some impact categories, but not for all. [•] The most important assumption results quantity and quality of energy substituted. [ABSTRACT FROM AUTHOR]