Abstract
Dual upflow reactive filtration using hydrous ferric oxide coated sand is used to meet the ultralow 0.05 mg/L total phosphorus discharge limits at a 1.2 million liters per day (0.32 million gallons per day) water resource recovery facility in Plummer, Idaho, in the United States. A life cycle assessment (LCA) of this reactive filtration installation was carried out to determine and quantify the critical impact sources in the system with a focus on CO2 equivalent (CO2e) global warming potential and other eco-impacts. Alternative what if scenarios with relevant process modification show trade-offs between the impact categories. Key results that show comparative reduction of global warming potential include use of Fe vs. Al metal salts, use of renewable energy, and the energy efficiency benefit of optimizing process inputs, such as compressor air pressure, to match operational demand. The LCA shows a 2 x 10-2 kg CO2e footprint per cubic meter of water, with 47% from housing concrete, and an overall freshwater eutrophication impact reduced by 99% versus no treatment. The use of renewable hydropower energy at this site isolates construction concrete as a target for reducing CO2e footprint.
Notes:
SimaPro - PRe Sustainability 9.2.0.2 PhD Life Cycle Analysis software is required to utilize these data