Life cycle inventory for thermal treatment of waste solvent from chemical industry: a multi-input allocation model

Waste solvent incineration is an important issue in life cycle assessments (LCAs) dealing with chemical products and/or processes. Nearly all chemical products and processes involve organic solvents, and incineration is often the favoured solution to waste solvent treatment as it can deal with a large variety of solvent types and quantities. At present, there are no generic models for waste solvent incineration which allow integrating this technology as a unit process in LCA. As waste solvents as a rule are incinerated as a mixture of several solvents, an allocation problem occurs: measurements of the consumption of ancillaries and energy carriers, and of emission of pollutants and generation of co-products, always refer to the mixture of waste solvents. However, in LCAs usually waste specific data is needed. To solve this problem we developed a multi-input allocation model of the incineration process. A comprehensive case study on a waste solvent incineration plant from chemical industry provided the necessary data. The results from the multi-input allocation modelling are consumption and emission factors which facilitate the calculation of solvent specific life cycle inventory results.