Emergy analysis and environmental indices applied to a company producing aluminium extruded bars

In this paper we apply two methodologies to a company that produces aluminium extruded bars: (1) the ‘pollutant interaction matrix method’, which allows the calculation of a global environmental protection index (Ep) in order to verify the eco-compatibility of the industrial activity, and (2) emergy analysis, a methodology used to evaluate the sustainability of an activity. The first methodology, which is applied to evaluate the environmental pollution risk, requires defining, for the whole industrial process, sectors of activities (defined as construction sites where activities of the same type are carried out) and a set of parameters (t = duration of pollution effect, P = quantity of pollutant produced, G = hazard of the pollutant) for each activity. Furthermore, to obtain information on the environmental cost of the whole industrial process, in terms of use of resources (fuel, electricity, water, etc.) we apply the emergy methodology as a complementary index for a global evaluation of sustainability. The environmental index results show that although the evaluated Epratio has a very low value (0.18), indicating that the whole process is non-polluting, some activities of the industrial process generate local pollution which could be dangerous for the workers’ health. The emergy analysis indicates that the most remarkable emergy flows are mainly associated with the use of aluminium panels and the consumption of electricity and methane.