Influence of impact assessment methods in wastewater treatment LCA

Facing the increase of environmental concern in the water treatment field, stakeholders need reliable decision support tools to assess environmental performances of urban and industrial wastewater systems. To discuss how life cycle assessment (LCA) can be applied to wastewater treatment projects, such an assessment has been performed through a case study on a full-scale plant. Methodological issues that had to be dealt with are briefly exposed. Five life cycle impact assessment (LCIA) methods have been used: CML 2000, Eco Indicator 99, EDIP 96, EPS and Ecopoints 97. Consistent assessment between these methods has been obtained for greenhouse effect, resources depletion and acidification. Eutrophication is correctly estimated if one looks at the potential impact of a treatment scenario but not at the characterization of the eutrophication state of a specific receiving stream. Work is needed concerning human toxicity as large discrepancies are noticed between the impact assessment methods.