Carbon Benefits of Drinking Water Treatment Electrification

Abstract

Water treatment electrification, or the substitution of chemically-driven processes for electricity-driven processes to produce equivalent water quality, will be critical to decarbonizing our water supply. This work quantitatively assesses the carbon reduction potential of electrified unit processes for the removal of suspended solids, divalent ions, and organic compounds relative to chemically-intensive conventional coagulation, softening, and sorption processes. Several electrified technologies─including electrocoagulation, nanofiltration, and packed tower aeration─already reduce carbon emissions relative to the corresponding chemically-driven treatment processes under certain water quality conditions. Other electrified substitutes increase net carbon emissions for the carbon intensity of the 2020 grid but will reduce carbon emissions by 2050 as the electricity grid decarbonizes over the expected lifespan of the unit process. For electrified processes that are more carbon intense than conventional processes, we identify electricity consumption targets that would yield breakeven carbon emissions. Finally, we evaluate the potential for intensified treatment technologies (e.g., use of nanofiltration for simultaneous organics concentration reduction and divalent ion removal) to reduce carbon emissions when a single purpose application would not.