Sustainability assessment of alternative waste-to-energy technologies for the management of sewage sludge.

The management of sewage sludge still represents a challenge in the EU sustainability plan for biowaste. Although there are consolidated alternatives for the valorization of sewage sludge (incineration, pyrolysis and gasification), technical issues related to heavy metals and other pollutants are not sufficiently understood considering the whole waste-to-energy process. In addition, societal-economic and environmental aspects are usually not included in the evaluation of these conversion technologies.