Coal-Fired Power Plant Wet Flue Gas Desulfurization Bromide Discharges to U.S. Watersheds and Their Contributions to Drinking Water Sources

Abstract

Wet flue gas desulfurization (FGD) wastewater discharges from coal-fired power plants may increase bromide concentrations at downstream drinking water intakes, leading to increased formation of toxic disinfection byproducts (DBPs). Despite this, bromide was not regulated in FGD wastewater in the 2015 Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Point Source Category (ELGs). Case-by-case management was recommended instead, depending on downstream drinking water effects. The present work seeks to identify U.S. regions where power plant discharges could affect drinking water. Bromide loads were evaluated for all coal-fired power plants operating wet FGD, and flow paths were used to identify downstream surface water sources. A population-concentration metric was used to evaluate the effect of wet FGD on downstream drinking water and the vulnerability of drinking water to upstream discharges. On a hydrologic region level, results indicate the Ohio, South Atlantic Gulf, and Missouri Regions are the most likely to see effects of power plant bromide discharges on populations served by surface water. Increased refined coal use, which may be treated with bromide, contributes to uncertainty in potential bromide effects on drinking water. Measurement of bromide concentrations in wet FGD discharges would reduce this uncertainty, and control of bromide discharges may be needed in some watersheds.