PARENT SESSION
MP1 Lifecycle inventory after 14041; new developments in modelling
3:00 PM to 6:30 PM, Monday, 07 May 2001
Session Chair: B. Weidema
Room 1

(079) The development of a method to include municipal wastewater and sludge treatment in LCI/LCA.

Granath, Jessica¹, Ek, Mats¹, Henshaw, Carole², King, J. M. Henry², Lindfors, Lars-Gunnar¹, Sundqvist, Jan-Olov¹, Wachtmeister, Alexandra¹, ^{1 2}

ABSTRACT- LCI/LCA methodology stipulates that all activities belonging to the technosphere and which are needed to fulfil the function of the studied system should be included within the system boundaries. Thus, any form of wastewater and sludge treatment that aqueous effluents receive prior to discharge to the environment should be included in the inventory analysis and inventory output data should include emissions after treatment. This paper describes the development of a life cycle inventory model for wastewater and sludge treatment that allows complete flexibility to model country specific wastewater and sludge treatment for seventeen European countries. The model concept is similar to that normally used in LCI modelling of electricity production, i.e. a set of wastewater and sludge treatment modules is combined with country specific treatment statistics, thereby generating country specific LCI results. The model is based on material flows. The wastewater resulting from the use of a product (cleaning product, detergent etc.), is specified through its content of different compounds. Emissions to air, water and soil are determined by the wastewater composition and the wastewater and sludge treatment mix. The model is illustrated by LCI results for two products, a zeolite based compact powder and a phosphate based compact powder. The results stress the importance of including the wastewater and sludge treatment phases in the LCI. These phases have a significant influence on some impact categories (e.g. eutrophication) and some emissions (e.g. methane). The results also indicate the importance of the country specific approach, since the results differ significantly between the studied countries.

Key words: life cycle inventory, material flow analysis, wastewater treatment, sludge treatment