Evaluation of potential environmental impacts related to two organic waste treatment options in Italy

Abstract

This paper aims at evaluating the environmental impact of two types of organic fraction of municipal solid waste treatment techniques – composting and anaerobic digestion with post-composting – by using the life cycle assessment (LCA) methodology. The analysis concerns a facility of municipal solid waste selection and composting, which is located in Italy and where currently there is only a composting line. Two LCA implementations will be presented -- one on the current status and one on the future option – where, according to the plant expansion plan, an anaerobic digestion line is expected to be introduced. This line will allow obtaining electricity and heat as a result of a cogeneration process fuelled by the produced biogas. Following the characterisation results, currently the compost production phase assumes the highest values in 9 out of 18 analysed impact categories, while the landfill phase prevails in the remaining 9. As far as the option to be implemented in the future is concerned, the stage that affects the most (for 8 categories) is sewage treatment, followed by landfill (6 of them) and finally by the compost production (for the remaining 4). The parallel analysis of the two organic waste treatment methods showed that the best one is the anaerobic/composting digestion solution, obtaining lower scores with respect to the sole composting option (apart from the photochemical formation of oxidants impact category).