Johan Pettersen

Lifecycle Assessment and Lifecycle Costing of Aluminium Wrought-to-Wrought Recycling

The aluminium scrap market is undergoing rapid changes which will trigger off new recycling strategies. As the cast scrap market saturates it will become economically feasible to apply scrap also in aluminium wrought alloy production. As part of an EU project, Sustainable and efficient Production of Light weight solutions (SuPLight) a method for assessing life cycle environmental and economic consequences of applying aluminium scrap in high-end products has been developed. In this work, the method has been applied to assess life cycle environmental and economic impacts for six scenarios, embracing five various strategies for scrap treatment. This includes processes in material and component production, as well as fuel use during operation of vehicle and end-of-life treatment. The model for scrap strategies includes three grades of sorting and separation, plus simple refining by low-temp electrolysis and fluxing, and refining by Hoopes process. Not surprising, we find that sorting is beneficial compared to refining. More notable, perhaps, is the relative large difference between scenarios with regards to the environmental impacts considered. Finally, we discuss benefits from the life-cycle evaluation of scrap scenarios and use of the tool in business development.

Greenhouse gas emissions from life cycle assessment of Norwegian food production systems

Abstract This paper presents an assessment of atmospheric emissions of greenhouse gases (GHGs) and associated land use for the production of milk, beef, grain and potatoes. It compares the less intensive (i.e. organic) farming system with the more intensive (i.e. conventional) food production system. The emission sources, trade-offs with land and potential for reduction of GHG emissions were analysed. The sources for farm accounts data on inputs and outputs are representative farm types constructed from data from the Norwegian Farm Accountancy Data Network. The analysis was carried out with life cycle assessment, including processes from manufacturing of inputs to farms, and on-farm production up to the farm gate. The results show that it is worthwhile considering a greater proportion of food energy from vegetable rather than from animal products, analysing grass-based meat production in more detail and reducing mineral fertilizer use.

Marine ecotoxic effect of pulse emissions in life cycle impact assessment

Characterization factors for ecotoxicity in life cycle impact assessment are traditionally calculated as the product of effect and fate factors. Steady-state multiple compartment models are used to calculate the fate factor, while effect factors are derived from species sensitivity distributions (SSDs) for multiple substances using average or marginal gradients. Others have shown that steady-state multicompartment models can be used to calculate characterization factors if linear dose-response functions are used. Average gradients are linear dose-response functions per definition. Marginal gradients are first-order Taylor approximations of the effect function and require marginal exposure at all points of the compartment. Instantaneous mixing, giving marginal exposure within compartments, is an implicit assumption of the multicompartment model. This paper investigates if the assumption of marginal exposure results in significant errors for the characterization factor. Ecotoxic effect of pulse emissions is simulated in a transient three-dimensional single compartment model of the marine aquatic environment. Results show that the error in characterization factors for the Taylor approximation is less than a factor of two for multisubstance SSDs assuming concentration addition only in the aggregation of toxic effect of substances. Assuming a combination of response and concentration addition may result in a deviation of several orders of magnitude.