November 17, 2017
Overview and Status of the Steam Electric Power Generating
Effluent Limitation Guidelines (ELGs) and Standards
Overview: What Is It?
 Best Available Technology Economically Achievable
The Clean Water Act (CWA) directs the Environmental
(BAT) generally represents the best existing
Protection Agency (EPA) to regulate discharge of
performance in the industrial category or subcategory.
pollutants into U.S. waters. Such discharges are prohibited
Factors considered include the cost of achieving effluent
without a permit. Thus, industrial dischargers and others
reductions and processes employed.
must obtain permits from states or EPA that set limits on
pollutants in their effluent. To guide the limits set in
 New Source Performance Standards (NSPS) reflect the
permits for industrial dischargers, EPA issues Effluent
reductions achievable based on the best available
Limitation Guidelines (ELGs), or technology-based
demonstrated control technology. EPA is directed to
standards, for categories of industrial dischargers. Since
take into consideration the cost of achieving the effluent
1972, EPA has promulgated ELGs for 59 industrial
reduction and any non-water-quality environmental
categories, including the steam electric power industry.
impacts and energy requirements.
In November 2015, EPA published revised ELGs and
 Pretreatment Standards for Existing Sources (PSES) are
standards for the steam electric power industry to replace
designed to control the discharge of pollutants that pass
rules issued in 1982. EPA determined that new ELGs were
through, interfere with, or are otherwise incompatible
necessary to reflect changes in the industry. For example,
with the operation of a POTW. PSES standards are
technology improvements over the past few decades
analogous to BAT for direct dischargers.
reduced hazardous air emissions but increased discharges of
certain pollutants, primarily heavy metals, to surface
 Pretreatment Standards for New Sources (PSNS) are
waters. EPA promulgated the 2015 rule to address those
designed for the same purpose as PSES. EPA considers
water quality impacts by establishing new ELGs for six
the same factors in promulgating PSNS as it does in
wastestreams from steam electric power plants. (For more
promulgating NSPS.
details on the rule see CRS Report R43169, Regulation of
Power Plant Wastewater Discharges: Summary of the EPA
CWA Section 301(d) directs EPA to review existing ELGs
Final Rule.) In September 2017, EPA finalized a rule
at least every five years and, if appropriate, revise them.
postponing compliance deadlines for two wastestreams to
During the 2005 review of existing ELGs, EPA identified
allow the agency time to potentially revise the limits set in
the rules governing the steam electric power point source
the 2015 rule (see “Current Status”).
category for possible revision based in part on data showing
that the industry ranked high in discharges of toxic and
Background of the Rule
nonconventional pollutants. EPA initiated a study,
ELGs are national regulations for industrial wastewater
completed in 2009, that found that the 1982 regulations did
discharges that set technology-based numeric limits for
not adequately address the pollutants being discharged and
specific pollutants. For point sources that introduce
had not kept pace with changes that occurred in the industry
pollutants directly into U.S. waters—“direct dischargers”—
over the last several decades—specifically the increase of
states or EPA incorporate the limits set in ELGs into the
flue gas desulfurization systems, or scrubbers, at coal-fired
National Pollutant Discharge Elimination System (NPDES)
power plants to control air pollution. While scrubbers
permits that they issue. For sources that discharge to
reduce emissions of harmful pollutants into the air, some
publicly owned treatment works (POTWs)—“indirect
create a significant liquid wastestream. In addition,
dischargers”—EPA promulgates pretreatment standards
discharges from coal combustion residual (CCR) surface
that apply to those sources and are enforced by POTWs and
impoundments at some steam electric power plants have a
federal and state authorities.
potential to degrade water quality. EPA also identified
several wastestreams that are relatively new to the industry
The CWA established several types of effluent limitations.
(e.g., carbon capture wastewater) and others for which there
Those applicable to the 2015 rule are as follows:
is little characterization data (e.g., gasification wastewater).
 Best Practicable Control Technology Currently
In 2009, environmental groups sued EPA to compel them to
Available (BPT) is based on the average of the best
commit to a schedule for issuing revised ELGs for this
existing performance of plants within the industry or
industry. Pursuant to a consent decree that it entered into
subcategory. In selecting BPT, EPA considers factors
with these litigants, EPA promulgated the final rule, which
including the cost of applying the control technology in
was published November 3, 2015. The 2015 rule contains
relation to the effluent reduction benefits, equipment
BAT and PSES standards for existing sources and NSPS
and facility age, and processes employed.
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link to page 2 Overview and Status of the Steam Electric Power Generating Effluent Limitation Guidelines (ELGs) and Standards
and PSNS requirements for new sources, which apply to six
Current Status
wastestreams (See Table 1.)
Following promulgation of the final ELG rule in 2015,
various stakeholders filed judicial petitions for review,
Table 1. Pollutant Discharge Limitations and
which were consolidated in the U.S. Court of Appeals for
Technology Basis for 2015 Steam Electric Generating
the Fifth Circuit (Southwestern Elec. Power Co. v. EPA, 5th
Point Source Category Effluent Limitations
Cir., 15-60821, filed November 20, 2015). Industry groups
Guidelines and Standards
and utilities argued, among other things, that EPA withheld
essential data, methodologies, and analyses from the public
Pollutant
Pollutant
record as confidential business information. Other groups
Discharge
Discharge
argued that EPA acted arbitrarily by not requiring more
Limitations and
Limitations and
stringent controls on discharges of bromide to surface
Technology Basis
Technology Basis
waters. In March and April 2017, EPA received petitions
for Existing
for New Sources
for administrative reconsideration of the final rule.
Sources (BAT
(NSPS and
According to EPA, the petitions raised “wide-ranging and
Wastestreams
and PSES)
PSNS)
sweeping objections to the rule” and included new data that
the agency wanted to review. In April 2017, the
Flue Gas
Numeric limitations
Numeric limitations
Administrator announced his decision to reconsider the
Desulfurization
on arsenic, mercury, on arsenic, mercury,
rule. The Fifth Circuit granted EPA’s request to sever and
(FGD)
selenium, and
selenium, and Total
hold portions of the case in abeyance that are related to
Wastewater
nitrate/nitrite as N
Dissolved Solids
judicial review of the BAT and PSES for bottom ash

(TDS)
transport water, FGD wastewater, and gasification
Chemical

wastewater while EPA reconsiders the rule.
precipitation +
Evaporation control
biological treatment
technology
On September 18, 2017, EPA published a final rule
postponing the earliest compliance dates from November
Fly Ash
Zero discharge of
Zero discharge of
2018 to November 2020 for BAT effluent limitations and
Transport Water
pollutants
pollutants
PSES for two forms of waste—flue gas desulfurization


wastewater and bottom ash transport water (82 Federal
Dry handling
Dry handling
Register 43494). In explaining its rationale, EPA stated that
control technology
control technology
it intends to conduct a new rulemaking regarding the
appropriate technology bases and associated limits for the
Bottom Ash
Zero discharge of
Zero discharge of
BAT and PSES requirements applicable to the two
Transport Water pollutants
pollutants
wastestreams “in light of new information not contained in


the record for the 2015 rule and the inherent discretion the
Dry handling or
Dry handling or
agency has to reconsider past policy decisions consistent
closed loop control
closed loop control
with the CWA and other applicable law.” The agency also
technology
technology
stated that it does not intend to conduct a rulemaking that
would potentially revise the rule as it pertains to ELGs and
Flue Gas Mercury Zero discharge of
Zero discharge of
standards for the other wastestreams covered by the rule. As
Control
pollutants
pollutants
such, EPA is not changing the compliance dates for the
Wastewater


BAT limitations and PSES established by the 2015 rule for
Dry handling
Dry handling
those wastestreams.
control technology
control technology
Also of potential relevance to power plant owner/operators
Gasification
Numeric limitations
Numeric limitations
are federal standards, finalized in 2015, that are applicable
Wastewater
on arsenic, mercury, on arsenic, mercury,
to landfills and surface impoundment ponds that contain
selenium, and TDS
selenium, and TDS
coal combustion residuals (also known as “coal ash”). EPA


promulgated the regulations in accordance with its
authorities in the Resource Conservation and Recovery Act.
Evaporation control
Evaporation control
Among other requirements, the standards specify conditions
technology
technology
under which certain surface impoundment ponds may be
Combustion
Impoundment
Numeric limitations
required to close. For more information, see CRS Insight
Residual Leachate control technology
on arsenic and
IN10585, State Programs for “Coal Ash” Disposal in the
(equal to BPT
mercury
WIIN Act .
standard)

Chemical
Laura Gatz, Analyst in Environmental Policy
precipitation control
IF10778
technology
Source: EPA, “Effluent Limitations Guidelines and Standards for the
Steam Electric Power Generating Point Source Category; Final Rule,”
80 Federal Register 67838-67903, November 3, 2015.
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Overview and Status of the Steam Electric Power Generating Effluent Limitation Guidelines (ELGs) and Standards


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