Novel field trial for ocean alkalinity enhancement using electrochemically derived aqueous alkalinity

Allison M Savoie^1*Mallory Ringham²Carolina Torres Sanchez¹Brendan R Carter^3,4Sean Dougherty⁴Richard Alan Feely⁴Dave Hegeman²Julian Herndon^3,4Tarang Khangaonkar^1,5Jeremy Loretz²Tyson Minck²Todd Pelman²Lakshitha Premathilake^1,5Chinmayee Subban^1,6Jesse Vance²Nicholas David Ward⁷

• ¹Coastal Sciences Division, Pacific Northwest National Laboratory Sequim, Sequim, United States
• ²Ebb Carbon Inc, South San Francisco, United States
• ³Cooperative Institute for Climate Ocean and Ecosystem Studies, Seattle, United States
• ⁴NOAA Pacific Marine Environmental Laboratory, Seattle, United States
• ⁵Salish Sea Modeling Center, University of Washington Tacoma, Tacoma, United States
• ⁶Department of Material Science and Engineering, University of Washington, Seattle, United States
• ⁷Pacific Northwest National Laboratory Sequim, Sequim, United States

carbon dioxide removal, ocean alkalinity enhancement, coastal outfall, wastewater treatment, field experiment, ocean acidificationOcean alkalinity enhancement (OAE) may serve as a feasible means of mitigating rising atmospheric CO2 concentrations in the future, as it is potentially capable of Gt-scale carbon dioxide removal (CDR). Numerous studies have tested various methods of OAE in laboratory or mesocosm studies. However, few field trials have been conducted thus far to release alkaline feedstock into the surface ocean. This manuscript details a first-of-its-kind dispersal of electrochemically derived aqueous alkalinity using the wastewater treatment facility at the Pacific Northwest National Laboratory in Sequim, WA. The alkaline signal was modeled at the facility outfall and monitored throughout the wastewater treatment facility. Description of the scale of the study and monitoring results are valuable input for the mCDR community as more experiments advance to field trial stages and require data for discharge permitting. This research is well-suited for the scope of the special research topic we are submitting the manuscript to, titled "Environmental Engineering Perspectives on Ocean-Based Carbon Dioxide Removal" at Frontiers in Environmental Engineering, as this manuscript focuses on the feasibility of using multiple engineered systems for the deployment and monitoring of OAE.