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La dernière décennie a vu l’analyse du cycle de vie (ACV) s’imposer comme cadre méthodologique de référence pour l’évaluation quantitative des impacts environnementaux d’un produit ou d’un système de production. Bien que déjà largement utilisés pour les produits manufacturés et les produits de grande consommation (éco-étiquetages), son application à l’assainissement est un sujet d’étude plus récent. L’article présente des résultats d’ACV obtenus pour deux types de stations d’épuration de petites et moyennes collectivités. Il examine ensuite le système d’assainissement dans sa globalité en présentant les contributions respectives de la station et du réseau de collecte aux différents impacts environnementaux. Il dresse enfin les limites actuelles de l’approche ACV pour l’assainissement et les perspectives de son utilisation comme outil décisionnel complémentaire au choix des filières de traitement et de leur gestion technique.

International audience; This work investigated the impact of aeration control strategy on energy consumption and nitrous oxide (N2O) emission in a full-scale wastewater treatment plant. Two identical activated sludge processes treating the same effluent but operated with different aeration control strategies were compared. Aeration tank 1 was operated with a new control strategy favouring the simultaneous nitrification denitrification (SND) whereas aeration tank 2 was operated with a conventional control strategy with distinct nitrification and denitrification phases. Results indicated that whereas the N2O emission factor was comparable in both systems (in the order of magnitude of 0.004% of the influent TKN load), N2O emission pattern was dependent on the adopted aeration control strategy. It has been observed that high aeration

International audience; This work investigated the impact of aeration control strategy on energy consumption and nitrous oxide (N2O) emission in a full-scale wastewater treatment plant. Two identical activated sludge processes treating the same effluent but operated with different aeration control strategies were compared. Aeration tank 1 was operated with a new control strategy favouring the simultaneous nitrification denitrification (SND) whereas aeration tank 2 was operated with a conventional control strategy with distinct nitrification and denitrification phases. Results indicated that whereas the N2O emission factor was comparable in both systems (in the order of magnitude of 0.004% of the influent TKN load), N2O emission pattern was dependent on the adopted aeration control strategy. It has been observed that high aeration flow rates (aeration tank 2) were likely to promote N2O transfer from the gas phase to the liquid phase.