LCA. Using the same system boundary described above, LCA was carried out to quantify the life cycle environmental impacts of the system following the general methodology outlined in ISO 14040/14044. For consistency with TEA, 1 tonne of COD removal was chosen as the functional unit of the analysis. While construction and O&M of all unit operations and equipment were included in the system boundary, project end-of-life was excluded due to lack of information about encapsulated systems. With the construction material, equipment, and O&M inputs and outputs (e.g., chemical use, electricity consumption, heat utility, bead replacement, fugitive emissions) estimated through system simulations and the design algorithms, corresponding life cycle inventory data and impact factors were gathered from the ecoinvent v3.8 database. Surrogate items or items in upstream production processes were used when a particular item was not available in the database (Table ). The life cycle impact assessment was conducted using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI v2.1). All nine impact categories evaluated by TRACI v2.1 were included in the simulations, with emphasis on the 100-yr global warming potential to represent carbon intensity (CI) in subsequent analyses.