Abstract
A comparative study of ASR treatment and recycling was conducted to evaluate the impact of four scenarios : landfilling, incineration followed by landfilling, melting followed by landfilling and melting followed by heavy metal recovery. Considering global warming, acidification, hazardous chemical substances (human toxicity), eco-toxicity and waste volume (landfill space occupied) as impact categories, the life cycle impact of each scenario was assessed based on an inventory of data obtained from the melting treatment of ASR and other processes and by making use of evaluation coefficients given in LIME2, which is a new version of LIME (Life cycle Impact assessment Method based on Endpoint modeling). Melting had the demerit of emitting more greenhouse gas than landfilling or incineration, but its merits of causing less damage to human health due to its smaller discharge of heavy metals and of requiring less space for landfilling outweighed this demerit. The difference between the merits and the demerit was larger when their effects on the ecosystem (biological diversity) were considered. It was found that the heavy metal recovery of fly ash in the melting process had a significant impact on the suppression of heavy metal discharge.
