Environmental sustainability of waste water ozonation

The EU FP6 NEPTUNE project is related to the EU Water Framework Directive and the main goal is to develop new and optimize existing waste water treatment technologies (WWTT) and sludge handling methods for municipal waste water. Besides nutrients, a special focus area is micropollutants (e.g. pharmaceuticals, heavy metals and endocrine disrupters). As part of this work a holistic based prioritisation among technologies and optimisations have been done. Tools for this prioritisation include life cycle assessment (LCA) and cost/efficiency. The LCA is performed as a comparative LCA and the concept of induced impacts as compared to avoided impacts is introduced in the life cycle impact assessment (LCIA) part. A relatively high number of micropollutants, especially pharmaceuticals, have been included. Furthermore, as novel approaches, preliminary methodologies for impact categories on pathogens and whole effluent toxicity have been developed. About 15 different waste water and sludge treatment technologies (or combinations) have been assessed. This paper will present the LCA results from running the induced versus avoided impact approach on one of the WWTTs, i.e. ozonation.