Overview of the Steam Electric Power Generator Effluent Limitation Guidelines and Standards

Updated October 1, 2020

Overview of the Steam Electric Power Generator Effluent

Limitation Guidelines and Standards

Overview

 Best Practicable Control Technology Currently

The Clean Water Act (CWA) directs the Environmental

Protection Agency (EPA) to regulate the discharge of

pollutants into waters of the United States. Such discharges

are prohibited without a permit. Thus, industrial dischargers

and others must obtain permits from states or EPA that set

limits on pollutants in their effluent. To guide the limits set

in permits for industrial dischargers, EPA issues Effluent

Limitation Guidelines and standards (ELGs)—technologybased standards—for categories of industrial dischargers.

Since 1972, EPA has promulgated ELGs for 59 industrial

categories, including the steam electric power industry—

which covers power plants that use nuclear or fossil fuels to

generate steam used to produce electricity.

In November 2015, EPA published revised ELGs (80

Federal Register 67838) for the steam electric power

industry to replace rules issued in 1982. EPA determined

that new ELGs were necessary to reflect changes in the

industry. For example, technology improvements since

1982, particularly at coal-fired power plants, reduced

hazardous air emissions but increased discharges of other

pollutants, primarily heavy metals, to surface waters. EPA

promulgated the 2015 rule to address those water quality

impacts by establishing new or additional requirements for

six wastestreams from steam electric power plants. In

September 2017, EPA finalized a rule postponing

compliance deadlines for two wastestreams to allow the

agency time to revise the limits set in the 2015 rule. In

November 2019, EPA proposed revisions to the 2015 final

rule for those two wastestreams. On August 31, 2020, EPA

finalized the rule, the “Steam Electric Reconsideration

Rule” (see “Current Status”).

Background and the 2015 Rule

ELGs are national regulations for industrial wastewater

discharges that set technology-based numeric limits for

specific pollutants. For point sources that introduce

pollutants directly into U.S. waters —“direct dischargers”—

states or EPA incorporate the limits set in ELGs into

National Pollutant Discharge Elimination System permits.

For sources that discharge to publicly owned treatment

works (POTWs)—“indirect dischargers”—EPA

promulgates pretreatment standards that are enforced by

POTWs and federal and state authorities.

The CWA requires industrial dischargers to achieve

specified levels of pollution control based on whether a

discharger is direct or indirect, a new or existing source,

and the category of pollutant discharged. The levels of

control pertinent to the 2015 rule are as follows:

Available (BPT) is based on the average of the best

existing performance of plants within the industry or

subcategory. In selecting BPT, EPA considers factors

including the cost of applying the control technology in

relation to the effluent reduction benefits, equipment

and facility age, and processes employed.

 Best Available Technology Economically Achievable

(BAT) generally represents the best existing

performance in the industrial category or subcategory.

Factors considered include the cost of achieving effluent

reductions and processes employed.

 New Source Performance Standards (NSPS) reflect the

reductions achievable based on the best available

demonstrated control technology. EPA is directed to

take into consideration the cost of achieving the effluent

reduction and any non-water-quality environmental

impacts and energy requirements.

 Pretreatment Standards for Existing Sources (PSES) are

designed to control the discharge of pollutants that pass

through, interfere with, or are otherwise incompatible

with the operation of POTWs. PSES standards are

analogous to BAT for direct dischargers.

 Pretreatment Standards for New Sources (PSNS) are

designed for the same purpose as PSES. EPA considers

the same factors in promulgating PSNS as it does in

promulgating NSPS.

CWA Section 304(m) directs EPA to annually review

existing ELGs to determine whether revisions are

appropriate. During its 2005 review, EPA identified the

steam electric power industry ELGs for possible revision

based in part on data showing that the industry ranked high

in discharges of toxic and nonconventional pollutants. EPA

initiated a study, completed in 2009, which found that the

1982 regulations did not adequately address the pollutants

being discharged and had not kept pace with changes in the

industry over the prior several decades. The study focused

primarily on coal ash handling operations and flue gas

desulfurization (FGD) systems (i.e., scrubbers) used at coalfired power plants to control air pollution. While scrubbers

reduce pollutant emissions into the air, some create a

significant liquid wastestream. The study further noted that

pollutants in coal combustion wastewater at some plants

have potential to degrade water quality when discharged or

leached into groundwater and surface waters.

In 2009, environmental groups sued EPA to compel the

agency to commit to a schedule for issuing revised ELGs

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Overview of the Steam Electric Pow er Generator Effluent Limitation Guidelines and Standards

for this industry. Pursuant to a consent decree, EPA

promulgated a final rule in 2015. The 2015 rule includes

BAT and PSES requirements for existing sources and NSPS

and PSNS requirements for new sources for six

wastestreams (Table 1). It also maintains BPT requirements

from the 1982 regulations for total suspended solids (TSS)

and oil and grease.

Table 1. Pollutant Discharge Limitations and Technology Basis

for 2015 Steam Electric Power Generator ELGs

Wastestreams

Flue Gas

Desulfurization

(FGD) Wastewater

Fly Ash Transport

Water

Bottom Ash (BA)

Transport Water

Flue Gas Mercury

Control

Wastewater

Gasification

Wastewater

Combustion

Residual Leachate

Existing Sources

(BAT and PSES)

New Sources

(NSPS and PSNS)

Numeric limitations on

arsenic, mercury,

selenium, and nitrate/

nitrite as nitrogen

Numeric limitations on

arsenic, mercury,

selenium, and total

dissolved solids (TDS)

Chemical precipitation

+ biological treatment

Evaporation control

technology

Zero discharge of

pollutants

Zero discharge of

pollutants

Dry handling control

technology

Dry handling control

technology

Zero discharge of

pollutants

Zero discharge of

pollutants

Dry handling or closed

loop control

technology

Dry handling or closed

loop control

technology

Zero discharge of

pollutants

Zero discharge of

pollutants

Dry handling control

technology

Dry handling control

technology

Numeric limitations on

arsenic, mercury,

selenium, and TDS

Numeric limitations on

arsenic, mercury,

selenium, and TDS

Evaporation control

technology

Evaporation control

technology

Equal to BPT limitation

for TSS

Numeric limitations on

arsenic and mercury

Impoundment control

Chemical precipitation

technology

control technology

Source: EPA, 80 Federal Register 67838-67903, November 3, 2015.

Current Status

Various stakeholders filed judicial petitions for review of

the 2015 rule, which were consolidated in the U.S. Court of

Appeals for the Fifth Circuit (Southwestern Elec. Power

Co. v. EPA, 5th Cir., 15-60821, filed November 20, 2015).

Industry groups and utilities argued, among other things,

that EPA withheld essential data, methodologies, and

analyses from the public record as confidential business

information. Other groups argued that EPA acted arbitrarily

by not requiring more stringent controls on discharges of

bromide. In March and April 2017, EPA received petitions

for administrative reconsideration of the rule. According to

EPA, the petitions raised “wide-ranging and sweeping

objections to the rule” and included new data the agency

wanted to review. In April 2017, the Administrator

announced his decision to reconsider the rule. The Fifth

Circuit granted EPA’s request to sever and hold portions of

the case in abeyance while EPA reconsidered the rule.

In September 2017, EPA published a final rule postponing

the earliest compliance dates for BAT and PSES

requirements for two wastestreams—FGD wastewater and

BA transport water—for a two-year period. EPA stated its

intention to conduct a new rulemaking regarding the

appropriate technology bases and limitations for those

requirements “in light of new information not contained in

the record for the 2015 rule and the inherent discretion the

agency has to reconsider past policy decisions consistent

with the CWA and other applicable law.” EPA also stated

that it did not intend to revise requirements for the other

wastestreams covered by the 2015 rule and, as such, did not

change their associated compliance dates.

In November 2019, EPA proposed a rule to revise the ELGs

applicable to FGD wastewater and BA transport water,

which it finalized on August 31, 2020. The 2020 rule

changes the technology basis for treatment of the two

wastestreams. EPA concluded that more affordable

technologies capable of removing similar pollutant amounts

became available since 2015. The 2020 rule establishes new

subcategories and varying requirements for high flow

facilities, low utilization units, and units retiring by 2028.

FGD wastewater: FGD wastewater dischargers that do not

fall into any of the new subcategories have numeric

limitations under the 2020 rule that are less stringent for

arsenic and selenium and more stringent for mercury and

nitrate/nitrite compared to the 2015 rule. Numeric

limitations for high flow facilities and low utilization

boilers are removed for selenium or nitrate/nitrite and

remain unchanged from the 2015 rule for arsenic and

mercury. Boilers retiring by 2028 are required only to meet

TSS limitations. The 2020 rule retains the voluntary

incentives program for direct FGD wastewater dischargers

established in the 2015 rule, which gives plants more time

to implement new BAT requirements if they adopt

additional process changes and controls that achieve more

stringent limitations. The 2020 rule’s limitations are less

stringent for arsenic, selenium, and TDS and more stringent

for mercury compared to the 2015 rule. The 2020 rule adds

limitations for bromide and nitrate/nitrite. It also extends

the timeline for the incentives program by five years.

BA transport water: While the 2015 rule established a zero

discharge standard for BA transport water, the 2020 rule

would establish a not-to-exceed 10 percent volumetric

purge limitation. For low utilization boilers, the 2020 rule

requires facilities to implement best management practice

plans and meet TSS limitations. Boilers retiring by 2028 are

be required only to meet TSS limitations.

Laura Gatz, Analyst in Environmental Policy

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Overview of the Steam Electric Pow er Generator Effluent Limitation Guidelines and Standards

IF10778

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