Waste treatment in product specific life cycle inventories

In product specific Life Cycle Assessment the environmental impacts resulting from the disposal of the product under study frequently have a strong influence on the overall result. Since the major disposal system - the Municipal Solid Waste Incineration (MSWI) and the Sanitary Landfill (SL) - are complex processes specially adapted for the treatment of a large variety of different types of waste with varying input composition, the direct determination of the environmental impacts coming from a single input component for example by measurements is not practicable. Two methods (Part I: MSWI, Part II: SL) of allocating the inventory positions caused by the processes MSWI and SL to individual input fractions are presented. The approaches described are based on process modelling for the calculation of the material and energy inputs and outputs of the disposal systems. For the MSWI process the material related allocation is carried out by means of a study of difference: The input/output balance is calculated with the process model for two variants with different input compositions. The input for the first variant consists of waste of average composition enlarged by a small amount of special waste fraction under study. In the second variant the calculation is done with an input consisting only of waste with average composition. The difference formed between the results of process calculation for both variants gives the effects of the treatment of the waste fraction under study in the disposal process.