End life tyres: Alternative final disposal processes compared by LCA

Life cycle assessment has been used to compare different processes for the end life treatment of exhausted tyres: combustion in a conventional waste-to-energy (WtE) process; substitution of conventional fuel in the cement clink process and two different hypotheses of reuse as filling material based on a cryogenic pulverisation process (CPP) or on a mechanical pulverisation process (MPP). The analysis shows that the fuel substitution in cement production and the use in WtE processes allow an interesting result in terms of avoided effects, mainly because of the avoided use of conventional fuels. Between these two alternatives, a better result is obtained with the fuel substitution in cement clink process. CPP and MPP for reuse as filling materials show worse results in terms of environmental impact with respect to the other alternatives, because of the high energy consumption related to the pulverisation processes.