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Coal-Fired Power Plant Wastewater Contributions to Bromide Concentrations in Drinking Water Sources

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thesis
posted on 01.12.2018, 00:00 by Kelly GoodKelly Good
Drinking water sources are affected by natural and anthropogenic processes that can alter their
treatability. Fossil fuel extraction and utilization activities have received considerable attention
recently since discharge of their associated wastewaters can increase bromide loading to source
waters and elevate bromide concentrations at downstream drinking water intakes. When bromide
is present in drinking water sources, the rate and extent of disinfection byproduct (DBP) formation
increases, and the speciation shifts toward brominated forms. Brominated DBPs exhibit higher
toxicity and are associated with negative health outcomes (e.g., cancer) at lower concentrations
than chlorinated DBPs. Thus, increases in brominated DBPs increase the health risk associated
with treated drinking water.
The objective of this work was to evaluate anthropogenic sources of bromide to surface waters and
their effects on drinking water sources, with a focus on coal-fired power plants operating wet flue
gas desulfurization (FGD) systems. Three main conclusions were reached through watershed-,
state-, and national-level analyses. First, bromide concentrations at a drinking water intake in the
lower Allegheny River in southwestern Pennsylvania are significantly affected by oil and gas
produced water and wet FGD discharges, particularly during low flow periods, and the
contributions are governed by the magnitude of the loads and the dilution capacity at the intake,
not geographic proximity. Power plant-associated loads could increase threefold if bromide
addition is selected as a process for mercury emission control. Second, considering a state-level analysis, there are significantly more people served by Pennsylvania drinking water systems that
are downstream of coal-fired power plant FGD discharges than previously identified, and multiple
power plants can affect a single drinking water intake. Third, although overall coal consumption
has declined, an increase in wet FGD-associated coal consumption, concurrent with increasing use
of halogen addition for meeting air quality regulations or securing federal tax credits, has resulted
in increases in bromide discharges from wet FGD that are affecting drinking water systems across
the country, particularly in the Ohio (HUC-05), Missouri (HUC-10) and South-Atlantic-Gulf
(HUC-03) hydrologic regions. Insufficient information on use of refined coal (which may or may
not have been treated with halogens) and on bromide addition for meeting mercury regulations
leads to significant uncertainty in the amount of bromide that will enter drinking water sources in
the future.

History

Date

01/12/2018

Degree Type

Dissertation

Department

Civil and Environmental Engineering

Degree Name

  • Doctor of Philosophy (PhD)

Advisor(s)

Jeanne VanBriesen