5. General conclusion

For wastewater treatment systems (as for waste treatment systems in general), remember that :

• the process influences the "downstream" quality of the treated flow;

• the "upstream" quality of the flow to be treated influences process performance.

By complying with the applicable standards, LCA methodology is a globally suitable tool for studying the environmental impacts of wastewater treatment plants.

Although potential eutrophication, as calculated in an LCA, remains a major impact of wastewater treatment, it should be noted that the processes used essentially avoid actual eutrophication of watercourses.

However, efforts should be made to supplement current toxicity and ecotoxicity databases to take better account of specific...