PARENT SESSION

6E - Life-Cycle Management
Hall 2
8:30 AM - 12:30 PM, Monday, 28 April 2003
Chair: Saur, K.¹, ¹
Co-chair: Frankl, P.², ²

(MO2/4) LCA as a basis for the life cycle management of waste water treatment.

Rebitzer, Gerald¹, Hunkeler, David², Braune, Anna¹, Stoffregen, Alexander¹, Jolliet, Olivier¹, ¹ Swiss Federal Institute of Technology Lausanne, Lausanne, VD, Switzerland² Aqua+Tech S.A., Geneva, GE, Switzerland

ABSTRACT- Waste water treatment is an advanced and established technology with growing relevance in all parts of the world. However, the implementation of end-of-pipe water treatment, which has been established in the industrialized countries since the 1970s and 1980s, without considering the up- and downstream burdens associated with the operation and the discharges, may not be the optimal solution. This, and other, studies show that it may even cause adverse effects. For example, a waste minimization strategy, without a life cycle perspective, may lead to the selection of non-sustainable options, not to mention poor financial allocation decisions. Therefore, in LCM not only the performance of the plant in regards to treatment efficiency (removal and decomposition of water borne emissions) should be addressed, but also the induced impacts up- and downstream of the plant. As an example, there are significant atmospheric emissions associated with water treatment. The presentation will introduce a modular life cycle model with which the complete system of waste water treatment, taking into account different technological options, was analyzed. It will be shown that environmental burdens are strong functions of the transport distances and disposal options for the end-of-life residues. Specifically, depending on the treatment process and chemicals used, different sludge qualities are produced, which have implications on the transport and sludge treatment processes. In order to assess trade-offs and to propose optimal solutions for improvements, the aforementioned model is based on an LCA product system, which allows for strategic decision support, taking the elements of the life cycle of water treatment into account. Results of different strategic decisions (e.g. incineration of sludge vs. use in agriculture or impacts of using organic flocculants) are discussed.

Key words: waste water treatment, life cycle management (LCM), trade-offs