A Methodology to Assess the Environmental Impacts of Upgrading Wastewater Infrastructure: A Case Study to Evaluate Energy Recovery from Black Water

As we pursue more sustainable water and wastewater systems it is vital that our planning and design process adapt to incorporate new assessment techniques such as life cycle assessment (LCA). A methodology for performing a comparative LCA of a proposed system upgrade is presented and applied to a case study considering an infrastructure upgrade to achieve decentralized energy recovery from black water. The operational phases of the existing system and proposed upgrade are evaluated and compared using the U.S. EPA's Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI). Certain impact factors (global warming potential and smog formation) were found to be sensitive to assumptions of methane and carbon dioxide off-gassing in collection systems. Ultimately, the methodology presented here is best utilized as one component of a broader planning and design process to facilitate the implementation of more sustainable water and wastewater systems.