A nearly $2 million award from NOAA will support a three-year project led by the University of Maryland Center for Environmental Science (UMCES) to explore how existing infrastructure like wastewater treatment plants could be used to help mitigate global warming. Oceans absorb about a third of carbon dioxide generated by human activities on our planet, helping to slow climate change, but the oceans are also becoming more acidic as a result, with impacts ranging from dying corals to struggling fisheries. This project will investigate how changing the chemistry of the wastewater, using a technique called ocean alkalinity enhancement, could help to remove carbon dioxide from the atmosphere and counteract deleterious impacts of ocean acidification on the marine ecosystem.
"When you make water more alkaline, changes in chemistry convert the dissolved carbon dioxide in the water into bicarbonate, a form of the inorganic carbon similar to baking soda dissolved in water," said Jeremy Testa, UMCES Associate Professor. "The effect is that there is less dissolved carbon dioxide in the water, meaning the ocean can take more carbon dioxide up from the atmosphere."
A key question the researchers will tackle involves estimating how long the carbon dioxide could remain in the ocean. "Bicarbonate can serve as a more stable reservoir to store carbon dioxide in seawater for a long time," said Wei-Jun Cai of the University of Delaware, a collaborator on the project.
The new project is part of a national initiative led by the White House to support research for new ocean-based climate solutions. Many wastewater facilities already amend wastewater with alkalinity to enhance treatment performance; thus, the use of alkalinity is well understood by utilities and permits to control the resulting effects on effluent pH already exist. This creates a potential 'shovel-ready' approach to climate change mitigation.
The Intergovernmental Panel on Climate Change considers removing carbon dioxide and storing it durably to be an essential contributor to limiting global warming. Despite the ocean’s large potential to store carbon, there are still many unknowns about the scalability, effectiveness and cost of marine carbon dioxide removal strategies, and their possible social and ecological impacts. This project will evaluate the feasibility, cost, and potential for carbon dioxide removal by alkalinity addition via existing wastewater treatment discharges. It will also provide a well-refined protocol for measuring and monitoring the amount of carbon removed in this context that can be applied to future efforts.
In collaboration with Planetary Technologies Inc., a carbon removal innovator focused on research, development, and deployment of ocean alkalinity enhancement, researchers will add alkalinity at a Hampton Roads Sanitation District wastewater treatment plant in Virginia.
In the first year, a test will ensure the safety and rigor of the dosing method. The team will closely monitor and control alkalinity dosing rates within the facility and monitor the receiving tidal waters for carbon removal and environmental impacts. During the second year, the researchers will identify other natural factors that modify the potential effect of carbon removal, such as the phase of the tide, the amount of algal growth in the water, and weather. During both tests, the team will monitor oyster growth and other environmental parameters. The results will inform an ocean model to better understand the benefits and impacts of a scaled-up version of these small field tests.
"We are grateful to NOAA for sponsoring this research," said Yuanyuan Xu, senior marine chemist at Planetary. "We are thrilled to be collaborating with such expert colleagues at UMCES and the University of Delaware. Through this work, we hope to accelerate the safe deployment of ocean alkalinity enhancement and contribute to our joint responsibility of restoring the climate and healing the ocean."
The project is led by Jeremy Testa with Ming Li (UMCES), Wei-Jun Cai (University of Delaware), and Yuanyuan Xu (Planetary Technologies, Inc.). NOAA’s Ocean Acidification Program led this funding opportunity on behalf of the National Oceanographic Partnership Program. It supports projects with partners from 47 institutions as part of the Investing in Coastal Communities and Climate Resilience provision under NOAA’s Integrated Ocean Observing System IRA priorities.