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-bycase 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 ef fect 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.

Power Plant Bromide Discharges and Potential Effects on DBP Formation

“…When such records are not available, it may be necessary for the regulator reviewing a permit application to require additional testing of the wastewater to assess the bromide loads. Alternatively, an estimation method based on coal usage and bromide concentrations reported for different coal types can be used (Good & VanBriesen 2018).…”

Flue Gas Desulfurization Wastewater Composition and Implications for Regulatory and Treatment Train Design

“…Existing tools, including PISCES , and the Electric Power Research Institute’s Toxic Release Inventory Tool, use this mass balance approach. These models are designed to provide nationwide estimates of trace metal releases to the environment and facilitate TRI reporting, rather than simulating interannual variability in trace element concentrations in FGD wastewater at the plant level (i.e., for individual plants) or predicting the costs of regulatory compliance. , There are also several mass balance models of trace element behavior at coal-fired power plants at the national ,, or subnational level , in the literature. However, the majority of these studies are focused on partitioning of trace elements to the gaseous phase.…”

“…However, the majority of these studies are focused on partitioning of trace elements to the gaseous phase. We are aware of two studies addressing liquid pollution, , but these have focused exclusively on Br and the total mass discharged rather than concentration in wastewater. Creating plant-level models to assist in ELG compliance requires combining the mass balance approach of these tools with volume estimates of FGD purge streams and validating model estimates against FGD wastewater quality samples from a diverse set of plants.…”

Investigation of the emission control of sulfur trioxide aerosols based on heterogeneous condensation and the deflectors tray of the desulfurization tower

“…However, there is no effective method to control the emission of sulfur trioxide aerosols. 14 The wet ue gas desulfurization (WFGD) system has been widely applied to control the emission of SO 2 . [15][16][17][18] Although wet desulfurization has a signicant effect on the removal of sulfur dioxide, the removal effect on the sulfur trioxide aerosols is not ideal.…”