Comparative Life Cycle Assessment of two advanced treatment steps for wastewater micropollutants: How to determine whole-system environmental benefits?

Advanced wastewater treatment (AWT) technologies are now considered to target urban micropollutants (MPs) before discharge into receiving water bodies and to comply with specific criteria for reuse. Extra energy and/or resources are necessary to achieve the elimination of MPs. Using the Life Cycle Assessment framework, this study assesses net environmental efficiencies for two AWTs (i) ozone systems (air-fed and pure oxygen-fed) and (ii) granular activated carbon filter. Sixty-five MPs with proven removal efficiency values and toxicity and/or ecotoxicity potentials were included in this study building on results from recent research. Consolidated Life Cycle Inventories with data quality and uncertainty characterization were produced with an emphasis on operational inputs. Results show that the direct water quality benefits obtained from AWT are outweighed by greater increases in indirect impacts from energy and resource demands. Future research should include water quality aspects not currently captured in life cycle impact assessment, such as endocrine disruption and whole-effluent toxicity, in order to assess the complete policy implications of MP removal strategies.

Impact assessment of a large panel of organic and inorganic micropollutants released by wastewater treatment plants at the scale of France

Micropollutants emitted by Human activities represent a potential threat to our health and aquatic environment. Thousands of active substances are used and go to WWTP through wastewaters. During water treatment, incomplete elimination occurs. Effluents released to the environment still contain part of the micropollutants present in the influents. Here, we studied the potential impacts on Human health and aquatic environment of the release of 261 organic micropollutants and 25 inorganic micropollutants at the scale of France. Data were gathered from national surveys, reports, papers and PhD works. The USEtox ® model was used to assess potential impacts. The impacts on Human health were estimated for 94 organic and 15 inorganic micropollutants and on aquatic environment for 88 organic and 19 inorganic micropollutants highlighting lack of concentration and toxicological data in literature. Some Polycyclic Aromatic Hydrocarbons and pesticides as well as As and Zn showed highest potential impacts on Human health. Some pesticides, PCB 101, βE2, Al, Fe and Cu showed highest potential impacts on aquatic environment.