Environmental performance of new wastewater and sludge treatment routes compared to conventional approaches

The value of life cycle assessments depends on their completeness and on how well the assessment answers the question asked. In the EU project ROUTES several case studies have been performed in order to evaluate innovative wastewater and sludge treatment scenarios against baseline scenarios, in order to understand whether the new ones perform better or worse from an environmental systems perspective and identify the hot spots in the studied systems from where the main environmental pressure originates. The performed LCA study assesses five impact categories, Global Warming Potential, Acidification Potential, Eutrophication Potential, Ozone Depletion Potential and Photochemical Ozone Creation Potential. This article discusses the relevance of the obtained results and identifies further assessments needed in order to provide a solid result.The study shows that, at present, although a limited number of impact categories are assessed, the studied energy-demanding technologies, like sequential batch biofilm granular reactor and membrane reactor, have a worse overall environmental performance compared to baseline scenarios, and points out electrical efficiency as the main area to put focus on to decrease the overall environmental impact. It also shows that the technologies aimed at sludge quality improvement exhibit a promising environmental performance, but further assessment, including LCA method development, is needed as the studied impact categories do not model the studied system in a thorough way when it comes to comparing agricultural application of sludge and other disposal options