Allocation of environmental loads in recycling: A model based in "qualitative value" of recycled material

When the life cycle of a product, material or service, studied in a Life Cycle Assessment (LCA) affects other life cycles not included in the system in analysis, it is necessary to apply allocation rules. Allocation can be defined, in LCA context, as the act of assigning the environmental loads of a system to the functions of that system in proportionate shares. Most of the available allocation methods are of generic application and do not take into account the quality of the materials to be recycled. The few that do take quality into account attribute to it a quantitative value. Methods that are both generic and scientifically correct are generally difficult to apply. Rules that are simple enough for a case by case application could lead to LCA studies that cannot be compared. This way, the best will be to dispose of simple methods but fair and mathematically correct methods available with a fundamentally driven application to a sector of economic activity. In this study a method of allocation is proposed which takes into account primarily the "qualitative" value of the material to be recycled. irrespective of being a pos-consumption product/material or a secondary material of a production process. Through a case study, the potential of application of the proposed method is demonstrated, in the recycling of products coming from wood industries and its derivatives, when compared with other allocation methods.