2.3. Analysis
After sorting the municipal solid waste, the determination of the moisture content of the waste was made at 75 °C in a drying oven for 24–48 h until a constant weight (TSE, 1992). The calorific value of the dried samples was determined with a bomb calorimeter according to ASTM D 5468-02. 0.9–1 g of each ground waste sample in an LECO AC-500 calorimeter was burned and the temperature change was determined to measure enthalpies of combustion. The heavy metals were also monitored using an ICP-OES (Perkin–Elmer). Prior to analysis, 0.2 g of each sample was digested in a microwave oven with concentrated 6 ml of HCl and 2 ml of HNO3 and diluted to 50 ml with water (EN 13657, 2002).
2.4. Life cycle assessment (LCA)
The methodology of LCA can be described by four interrelated phases, namely goal and scope definition, inventory analysis, impact assessment and interpretation.