Assessing the effect of local characteristics on environmental impacts of Constructed Wetlands by regionalized life cycle assessment

The goal of this paper is to assess the effect of regional characteristics on the environmental sustainability of Horizontal Subsurface Flow Constructed Wetlands using comparative regionalized Life Cycle Assessment. Regionalizaton was implemented in terms of input and outputs values, as well as considering impact assessment methods that consider regional aspects to estimate the environmental impact results. A case study for a Horizontal Subsurface Flow Constructed Wetlands treating municipal wastewater was assumed, and the system was assessed considering the installation of the constructed wetland in 5 different countries with distinct characteristics in terms of technologies, geographic location, climate conditions and electricity mix. The comparative life cycle assessment results showed important variations among the countries, which highlights the importance of taking into account a regionalized approach in order to assess the local specificities properly. An average relative standard deviation of 59 % for all regionalized impact categories was identified when comparing the LCA for the case study for different countries. So, the study successfully showed the importance of regionalization in constructed wetlands assignments and provided relevant recommendations for system enhancements in order to reduce environmental impact according to regional characteristics.