THE UNINTENDED EFFECTS OF A “CLEAN COAL” TAX CREDIT ON DRINKING WATER

Dr. Kelly Good '09 CE, Civil and Environmental Engineering

If you ask Civil and Environmental Engineering’s Dr. Kelly Good ’09 CE what a multibillion dollar “clean coal” tax credit has to do with drinking water, she will tell you it is a story of unintended consequences. A visiting assistant teaching professor, Dr. Good studies the interactions of infrastructure systems, most recently within the energy-water nexus to evaluate how regulations and development in the power sector affects drinking water quality and health.

“We need drinking water disinfection to protect us from waterborne disease outbreaks,” says Dr. Good. “However, chemical disinfectants, such as chlorine, react with other constituents in the water to form unintended disinfection byproducts, or DBPs, which are also harmful.” When drinking water sources also contain bromide, the DBPs that form are more toxic. Dr. Good’s work, which has informed U.S. Environmental Protection Agency power plant wastewater regulations, uses modeling to demonstrate that some power plants in the U.S. are contributing substantially to downstream drinking water bromide concentrations.

When the clean coal tax credit was introduced in the American Jobs Creation Act of 2004, many power plants began adding bromide to their coal, which controls air emissions of mercury. As these plants meet their air quality requirements, however, they sometimes produce wastewater—which, depending on their configuration, can include bromide—that goes into rivers that are also used as drinking water sources.

The U.S. Congress recently launched an investigation into this multibillion-dollar clean coal tax credit. Recent analyses show that while the goal was improved air quality, air pollution at plants burning refined coal has gotten worse. These chemical additives are not publicly reported, but halogens, such as bromide and iodide, are the most widely used. Dr. Good, who was recognized as a Siebel Scholar for her work on the effects of power plants on drinking water quality, explains “while the air quality discrepancy is the focus of the congressional investigation, the unintended effect of this tax credit on downstream drinking water quality and health are also important to consider. The types and amounts of additives used for the refining process are not publicly available, and thus, the downstream effects are uncertain and difficult to quantify.”

A related paper co-authored by Dr. Good titled “Modeling Trihalomethane Increases Associated with Source Water Bromide Contributed by Coal-Fired Power Plants in the Monongahela River Basin” appeared in Environmental Science & Technology (2020, 54, 2, 726– 734). At Villanova, Dr. Good continues to evaluate drinking water challenges, including a home water filter sampling project with U.S. EPA scientists.