Fuel and Flue‐Gas Additives

2016

The presence of bromide in rivers does not affect ecosystems or present a human health risk; however, elevated concentrations of bromide in drinking water sources can lead to difficulty meeting drinking water disinfection byproduct (DBP) regulations. Recent attention has focused on oil and gas wastewater and coal-fired power plant wet flue gas desulfurization (FGD) wastewater bromide discharges. Bromide can be added to coal to enhance mercury removal, and increased use of bromide at some power plants is expected. Evaluation of potential increases in bromide concentrations from bromide addition for mercury control is lacking. The present work utilizes bromide monitoring data in the Allegheny River and a mass-balance approach to elucidate bromide contributions from anthropogenic and natural sources under current and future scenarios. For the Allegheny River, the current bromide is associated approximately 49% with oil- and gas-produced water discharges and 33% with coal-fired power plants operating wet FGD, with 18% derived from natural sources during mean flow conditions in August. Median wet FGD bromide loads could increase 3-fold from 610 to 1900 kg/day if all plants implement bromide addition for mercury control. Median bromide concentrations in the lower Allegheny River in August would rise to 410, 200, and 180 μg/L under low-, mean-, and high-flow conditions, respectively, for the bromide-addition scenario.

Section: ■ Materials and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Current and Potential Future Bromide Loads from Coal-Fired Power Plants in the Allegheny River Basin and Their Effects on Downstream Concentrations

2016

“…Bromine is naturally present in coal in trace amounts, , and bromide addition to coal has been proposed to enable compliance with the Mercury and Air Toxics Standards (MATS). − During coal combustion, bromine is primarily converted to volatile hydrogen bromide (HBr) and subsequently to bromine gas (Br 2 ) upon cooling, with minimal transfer to residue streams such as fly ash and bottom ash (typically >90% remains in the vapor or gas phase). − Halogen species such as bromine, which would otherwise be released into the atmosphere out of the stack, are reduced to soluble ionic forms and are commonly observed in flue gas desulfurization (FGD) wastewater. , Additional details on bromide at power plants are provided in Supporting Information (SI) Section A.…”

Section: Introductionmentioning

confidence: 99%

Power Plant Bromide Discharges and Downstream Drinking Water Systems in Pennsylvania

2017

Coal-fired power plants equipped with wet flue gas desulfurization (FGD) systems have been implicated in increasing bromide levels and subsequent increases in disinfection byproducts at downstream drinking water plants. Bromide was not included as a regulated constituent in the recent steam electric effluent limitations guidelines and standards (ELGs) since the U.S. EPA analysis suggested few drinking water facilities would be affected by bromide discharges from power plants. The present analysis uses a watershed approach to identify Pennsylvania drinking water intakes downstream of wet FGD discharges and to assess the potential for bromide discharge effects. Twenty-two (22) public drinking water systems serving 2.5 million people were identified as being downstream of at least one wet FGD discharge. During mean August conditions (generally low-flow, minimal dilution) in receiving rivers, the median predicted bromide concentrations contributed by wet FGD at Pennsylvania intake locations ranged from 5.2 to 62 μg/L for the Base scenario (including only natural bromide in coal) and from 16 to 190 μg/L for the Bromide Addition scenario (natural plus added bromide for mercury control); ranges depend on bromide loads and receiving stream dilution capacity.

“…Coal-fired power plants are a significant source of bromide discharges to the environment due to the presence of bromine in coal, bromide addition to coal to reduce air emissions of mercury, , and bromide added to create refined coal to qualify for tax credit. − Bromine that would exit the plant in stack gases is captured in wet flue gas desulfurization (FGD) units deployed to reduce sulfur dioxide emissions to the air, leading to a wastewater with elevated bromide. − FGD wastewater bromide concentrations (typically on the order of 10–100 mg/L) are rarely monitored and are currently unregulated…”

Section: Introductionmentioning

confidence: 99%

“…27,30 The effect of increasing anthropogenic bromide concentrations in source waters on DBP formation and associated drinking water risk has also been reported elsewhere. 31,32 Coal-fired power plants are a significant source of bromide discharges to the environment due to the presence of bromine in coal, 33 bromide addition to coal to reduce air emissions of mercury, 34,35 and bromide added to create refined coal to qualify for tax credit. 36−38 Bromine that would exit the plant in stack gases is captured in wet flue gas desulfurization (FGD) units deployed to reduce sulfur dioxide emissions to the air, leading to a wastewater with elevated bromide.…”

Section: ■ Introductionmentioning

confidence: 99%

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

2018

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.