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Quantifying the Efficacy of Wastewater Alkalinity Enhancement on mCDR and Acidification Mitigation in a Large Estuary

Wastewater treatment plants could be used to enhance alkalinity as a carbon dioxide removal and ocean acidification mitigation approach. Credit: Chesapeake Bay Program

Why we care
Manipulating wastewater treatment plant procedures and discharge to enhance carbon removal is practical because of the current readiness of infrastructure to deliver alkalinity to the coastal ocean. Many wastewater facilities already treat wastewater with alkalinity, permits to allow alkalinity discharge already exist, and there are several known technologies that can increase alkalinity in wastewater streams. “This method of carbon removal is attractive because existing wastewater streams provide an opportunity to leverage existing infrastructure and to provide several co-benefits to the facility and the adjacent tidal waters” states Dr. Jeremy Testa of the University of Maryland Center for Environmental Science. Despite the existence of this “shovel-ready” carbon removal technology, there is still much uncertainty. These uncertainties center around costs, the efficacy of the process at a scale that can meaningfully impact coastal waters, and the environmental and biological impacts of various alkalinity-rich materials. “Our research will help quantify the feasibility of this approach” says Testa, and evaluate carbon removal and ocean acidification mitigation via alkalinity enhancement at a wastewater treatment plant in Chesapeake Bay. 

What we will do
This project will add alkalinity at a single wastewater treatment plan in the Hampton Roads Sanitation District in Virginia. In the first year, a 1-week 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 then concurrently monitor the receiving tidal waters for carbon removal and environmental impacts. During the second year, the researchers will perform a 4-week test. This longer test will help 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 like total suspended solids, nutrient concentrations, metals, and carbon chemistry variables. The results of these two tests will inform an estuary-ocean model to better understand the benefits and impacts of a scaled-up version of these small field tests. 

Benefits of our work
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.

Award amount: $1,864,561
IRA funding?
Funding source(s): NOAA
Project duration: 3 years

Jeremy Testa, University of Maryland Center for Environmental Science
Wei-Jun Cai, University of Delaware
Ming Li, University of Maryland Center for Environmental Sciences (UMCES)
Yuanyuan Xu, Planetary Technologies, Inc.

Image: Wastewater treatment plants could be used to enhance alkalinity as a carbon dioxide removal and ocean acidification mitigation approach. Credit: Chesapeake Bay Program

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The NOAA Ocean Acidification Program (OAP) works to prepare society to adapt to the consequences of ocean acidification and conserve marine ecosystems as acidification occurs. Learn more about the human connections and adaptation strategies from these efforts.

Adaptation approaches fostered by the OAP include:


Using models and research to understand the sensitivity of organisms and ecosystems to ocean acidification to make predictions about the future, allowing communities and industries to prepare


Using these models and predictions as tools to facilitate management strategies that will protect marine resources and communities from future changes


Developing innovative tools to help monitor ocean acidification and mitigate changing ocean chemistry locally


On the Road

Drive fuel-efficient vehicles or choose public transportation. Choose your bike or walk! Don't sit idle for more than 30 seconds. Keep your tires properly inflated.

With your Food Choices

Eat local- this helps cut down on production and transport! Reduce your meat and dairy. Compost to avoid food waste ending up in the landfill

With your Food Choices

Make energy-efficient choices for your appliances and lighting. Heat and cool efficiently! Change your air filters and program your thermostat, seal and insulate your home, and support clean energy sources

By Reducing Coastal Acidification

Reduce your use of fertilizers, Improve sewage treatment and run off, and Protect and restore coastal habitats

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You've taken the first step to learn more about ocean acidification - why not spread this knowledge to your community?

Every community has their unique culture, economy and ecology and what’s at stake from ocean acidification may be different depending on where you live.  As a community member, you can take a larger role in educating the public about ocean acidification. Creating awareness is the first step to taking action.  As communities gain traction, neighboring regions that share marine resources can build larger coalitions to address ocean acidification.  Here are some ideas to get started:

  1. Work with informal educators, such as aquarium outreach programs and local non-profits, to teach the public about ocean acidification. Visit our Education & Outreach page to find the newest tools!
  2. Participate in habitat restoration efforts to restore habitats that help mitigate the effects of coastal acidification
  3. Facilitate conversations with local businesses that might be affected by ocean acidification, building a plan for the future.
  4. Partner with local community efforts to mitigate the driver behind ocean acidification  – excess CO2 – such as community supported agriculture, bike & car shares and other public transportation options.
  5. Contact your regional Coastal Acidification Network (CAN) to learn how OA is affecting your region and more ideas about how you can get involved in your community
       More for Taking Community Action