EIA Guidejines for New Source
Petroleum Refineries and Coal Gasification Facilities
prepared for
Office of Federal Activities
U.S. Environmental Protection Agency
401 M Street, S.W.
Washington, D.C. 20460
under
EPA Contract 68-W2-0026, Work Assignment 34-1
SAIC Project Number 01-1030-03-6602-000
September 22, 1994
EPA Headquarters Library
4*9 Printed on Recycled Paper
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Table of Contents
TABLE OF CONTENTS
1. INTRODUCTION 1
Organization of These Guidelines 2
2. REGULATORY OVERVIEW . i 3
National Environmental Policy Act 3
The NEPA Process 4
The Clean Water Act 5
Process Water • 5
Application to the Petroleum Refining Industry 6
. Application to the Coal Gasification Industry 6
Stormwater '. : . 6
Application to the Petroleum Refining Industry . . . 7
Application to the Coal Gasification Industry 7
Application to Construction Activity 7
The Resource Conservation and Recovery Act 8
Non-hazardous Waste Requirements - Subtitle D 8
Underground Storage Tank Requirements - Subtitle I 9
Hazardous Waste Requirements - Subtitle C 9
Land Disposal Restrictions 9
Recycling and Reuse Exemptions and Provisions 9
Hazardous Waste Generators 10
Hazardous Waste Treatment, Storage, and Disposal Facilities 10
Ground Water Monitoring 10
Application to the Petroleum Refining Industry 11
Application to the Coal Gasification Industry 12
The Clean Air Act 12
Current Clean Air Act Requirements 12
New Source Review 12
New Source Performance Standards (NSPS) 13
National Emissions Standards for Hazardous Air Pollutants (NESHAPs) 14
Changes to Take Effect as 1990 Amendments Are Phased in 14
Federal Permit Program 14
New Source Review 14
Non-attainment Offsets IS
New Source Performance Standards (NSPS) IS
NESHAPS 15
Other Relevant Requirements IS
Clean Water Act Section 404 Permits 15
Endangered Species Act 16
National Historic Preservation Act 16
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Coastal Zone Management Act . . . . 17
Executive Orders 11988 and 11990 18
Executive Order 12898 (Environmental Justice) 18
Farmland Protection Policy Act 19
Rivers and Harbors Act 19
Wild and Scenic Rivers Act 19
Fish and Wildlife Coordination Act 20
3. TECHNOLOGY OVERVIEW 21
Petroleum Refining 21
Typically Used Processes 21
Desalting 23
Distillation and Fractionation 23
Cracking 24
Catalytic Cracking 24
Catalytic Hydrocracking 25
Thermal Cracking 25
Reconstruction 25
Hydrotreating 26
Alkylation 26
Polymerization 27
Isomerization 27
Reforming 27
Treating 28
Gas Concentration 28
Coking . . : 28
Asphalt Production 28
Lube Oil Production 28
Current Trends 29
Supply and Demand : 29
Configuration and Production Levels 30
Geographic Distribution 30
Raw Materials 31
Pollution Prevention * 31
Coal Gasification 33
Process Overview 33
Typical Configurations 35
Moving Bed Gasifiers 35
Fluidized Bed Gasifiers 35
Entrained Flow Gasifiers 35
Major Products 37
Fuel Gas 37
Electric Power 37
Hydrogen 37
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Synthetic Natural Gas (SNG) and Chemicals 38
Typical Processes 38
Coal Gasification 38
Combustion Engineering IGCC Repowering Project . . . 38
Lurgi Gasification/Great Plains Coal. Gasification Project 41
Texaco Gasifier/Tampa Electric IGCC Project 43
U-Gas Gasifier/Toms Creek IGCC Project 44
Corollary Processes 45
Shift Conversion 45
Methanation 46
Compression and Drying 47
Current Trends • 47
Supply and Demand 47
Improvements in Gasification Technology 48
Fuel Cells Based on Hydrogen and Oxygen (Air) 48
Scale of Operations 49
Geographic Distribution of Coal and Coal Gasification Projects 49
In-situ or Underground Coal Gasification 49
Combatting the Greenhouse Effect 50
4. ENVIRONMENTAL DOCUMENTATION 53
5. PURPOSE AND NEED 55
6. PROJECT ALTERNATIVES 57
Alternatives Available to EPA ' 57
Alternatives Considered by the Applicant 57
Alternatives Available to Other Permitting Agencies 58
Proposed Projects 58
7. AFFECTED ENVIRONMENT 61
Identifying and Characterizing the Affected Environment 61
Physical-Chemical Environment 61
Air Resources 61
Water Resources 62
Soils/Geology 63
Biological Environment 64
Vegetation 64
Wildlife 64
Ecological Interrelationships 64
Socioeconomic Environment 65
Community Services 65
Transportation 65
Population 66
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Employment 66
Health and Safety 66
Economic Activity 67
Land Use 67
Aesthetics 67
Cultural Resources 67
8. ENVIRONMENTAL CONSEQUENCES 69
Methods of Analysis 69
Determination of Significance 70
Comparisons of Impacts under Differing Alternatives 72
Summary Discussions • 72
Mitigation Measures 73
General Impacts 74
Impacts from Site Preparation and Construction 75
Habitat Alteration 75
Pollutant Generation 76
Socioeconomic Impacts 77
Land Use Change 77
Human and Institutional Resources; Community Structure 78
Loss of Historic or Cultural Resources 80
Impacts from Facility Operation '... 80
Air Quality 80
Water Quality 81
Soil Quality 82
Vegetation . . •. 83
Wildlife 84
Environmental Health and Safety 85
Land Use 86
Visual Resources : 86
Cultural Resources 87
Socioeconomic Impacts 87
Technology-Specific Potential Impact Reduction 88
Mitigating Impacts in Project Design 89
Petroleum Refining . . 89
Raw Materials Extraction, Transport and Storage 89
Gaseous Wastes 90
Stack Emissions 90
Fugitive Emissions 91
Air Quality Modeling 91
Waste Control and Residuals Disposal 95
Liquid Wastes 96
Aquatic Discharges 96
Process Wastes 97
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Stormwater 97
Water Quality Modeling 98
•Groundwater Contamination 99
Groundwater Modeling 99
Spills 101
Water Control and Residuals Disposal 101
Solid Wastes 102
Hazardous Wastes 102
Other Wastes 103
Waste Control and Residuals Disposal 104
Landfills 104
Recycling • 106
Other Impacts 106
Coal Gasification Impacts 107
Coal Extraction 107
Transportation 108
Coal Storage On-Site 108
Waste Storage and Disposal 108
Purification of Crude Gasifier Off-gas 110
Methods for Desulfurization of Coal Gasification Streams Ill
9. OTHER ISSUES 119
Consultation and Coordination 119
List of Preparers 119
References 119
10. REFERENCES 121
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VI
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Glossary
GLOSSARY
Alkylation:
Area source:
Aromatic:
BACT:
BDAT:
BMP:
Bituminous
coal:
Bottom ash:
Caustic:
Catalyst:
Catalytic
cracking:
A refinery process for combining isoparafin with olefm hydrocarbons.
Source of air emissions that is relatively uniform over a large surface area,
such as uncovered lagoons, storage piles, or slag heaps
Describes organic compounds containing at least one benzene ring
Best Available Control Technology
Best Demonstrated Available Technology
Best Management Practices
A dark brown to black coal, also known as soft coal, which is high in
carbonaceous matter and has 15-50 % volatile matter; yields significant
amounts of pitch or tar.
The heavier, coarser products of combustion which fall through grate at the
bottom of a furnace or boiler.
Typically refers to sodium hydroxide, but could be any other highly alkaline
or alkaline-producing chemical agent added to raise pH.
A substance or material which alters the speed of a chemical reaction; it can
be recovered virtually unchanged in form and amount after completion of the
reaction.
Cracking that involves the use of a catalyst.
Catalytic
hydrocracking: A high pressure petroleum refining process in which molecules too large and
complex for gasoline use have hydrogen added to them before being cracked
into smaller, more suitable molecules.
CEQ:
Char:
Council on Environmental Quality
Also known as low-temperature coke; it is produced at temperatures ranging
from 500-750 degrees Fahrenheit, and is comprised mainly of carbon and ash
impurities.
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Glossary
Coal
gasification:
Coking:
Cracking:
DAF floats:
The conversion of coal, char, or coke to a gaseous product by reaction with
air, oxygen, steam, carbon dioxide or mixtures of these.
The heating of heavy-weight petroleum distillation residuals in the absence
of oxygen in order to drive off remaining volatile organics and hydrogens,
yielding only the lowest boiling point organics and elemental carbon.
The breaking of large (higher boiling point) hydrocarbon molecules into
smaller (lower boiling point) ones.
%
The frothy top material containing suspended solids removed during the
dissolved air flotation process.
Dissolved air
flotation (DAF): A liquid-solid separation process where the main mechanism of suspended
solids removal is the change in apparent specific gravity of those suspended
solids in relation to the suspending liquid by attachment of small gas bubbles
formed by the release of dissolved gas to the solids.
Distillation:
Dry sorbent
injection:
EA:
EID:
EIS:
Endothermic:
Entrained bed
gasifier:
The separation of different petroleum components by selectively heating,
vaporizing and condensing compounds based on their different vapor
pressures.
\
Pollution control mechanism involving the injection of finely powdered solid
material into the flue gas stream upstream from paniculate removal systems.
Environmental Assessment
Environmental Impact Document
Environmental Impact Statement
Describing a reaction or process which takes in energy or heat.
A gasifier working on essentially powdered coal, it features the concurrent
down-flow, of both coal and steam-oxidant mixture, the generation of large
amounts of heat, and invariably slag.
Exothermic: Describing a reaction or process which releases energy or heat. .
Fluidized bed
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Glossary
gasifier:
In this design crushed coal that is less than one-quarter inch in diameter is
introduced onto a fluidized mixture of steam, air or oxygen and coal particles
at various stages of gasification.
Fly ash:
Fractionation:
FONSI:
GPGA:
Greenhouse
effect:
Hazardous
waste:
HRSG:
HSWA:
Hydrotreating:
IGCC:
Isomer:
Isomerization:
The finer paniculate, products of combustion carried in the gas stream from
a furnace or boiler. It may be comprised of incompletely combusted and/or
non-combustible materials.
A method of separation in successive stages, each stage removing a certain
portion of the crude oil stream
Finding of No Significant Impact
Great Plains Gasification Association
Term given to the phenomenon where infrared radiation, released by the
sunlight-warmed earth surface is intercepted by certain atmospheric gases;
these gases act much like windows on a greenhouse.
A hazardous waste is defined for the purposes of RCRA as one which is not
specifically excluded from hazardous waste regulation, and either exhibits a
hazardous characteristic (ignitability, corrosivity, reactivity or toxicity) or is
specifically listed as a hazardous waste.
Heat recovery steam generator
Hazardous and Solid Waste Amendments of 1984 to RCRA
Oil refinery catalytic process in which hydrogen is contacted with petroleum
intermediate or product streams to remove impurities, such as oxygen,
sulfur, nitrogen, or unsaturated hydrocarbons.
Integrated gasification combined cycle
One of two or more molecules having the same molecular weight and
number and kinds of atoms, but differing in the arrangement or structure of
those atoms.
A process in which a compound is changed in to an isomer, for instance, in
the conversion of n-butane into isobutane. In refining, a common
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Glossary
LAER:
isomerization is the conversion of normal straight chain paraffins to
branched-chain paraffins which help increase gasoline octane.
Lowest Achievable Emission Rate
Large quantity
generator: A hazardous waste generator defined in RCRA as one which generates
between 100 and 1,000 kg of hazardous waste per month.
Lignite: A soft coal, of relatively recent origin that is denser than peat, but not as
dense as other coals.
Line source: A source of air emissions, such as a road or railroad, which can be modelled
as a series of point sources.
LPG: Liquified Petroleum Gas
Medium quantity
generator: A hazardous waste generator defined in RCRA as one which generates
between 100 and 1,000 kg of hazardous waste per month.
Moving bed
gasifier:
MTR:
NAAQS:
NEPA:
NESHAPS:
New Source
Review:
NMFS:
Sometimes called a fixed bed gasifier, the design involves reacting a
stationary pile of coarse-sized coal atop a grate. As the coal is gasified, the
coal pile is reduced as part of the coal goes to gas, and part of the it falls
through the grate as ash; thus the pile appears to slowly move downward
though the grate.
Minimum Technical Standards
National Ambient Air Quality Standards
National Environmental Policy Act
National Emission Standards for Hazardous Air Pollutants
Clean Air Act required review for newly constructed facilities and
expansions resulting in increased emissions. Requirements under the review
are designed to prevent significant deterioration of air quality, and vary.
depending on whether the NAAQS have been met in the area in which the
facility is located.
National Marine Fisheries Service
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Glossary
Non-attainment
area: An area of the country in which the concentrations of a constituent regulated
under the Clean Air Act exceed the NAAQS; the area has not attained low
enough concentrations.
NPDES: National Pollutant Discharge Elimination System
NSPS: New Source Performance Standards
Point source: A single, discrete source of liquid or gaseous discharge, often modelled as
a point.
Polymerization: The chemical bonding of two or more identical molecules into a larger
molecule.
POTW: Publicly Owned Treatment Works
RCRA: Resource Conservation and Recovery Act
Small quantity
generator: A hazardous waste generator defined in RCRA as one which generates less
than 100 kg of hazardous waste per month.
Slag: A glassy substance formed when ash has been heated to the point of melting
and agglomeration.
Stormwater: Storm water runoff, snowmelt runoff, and surface runoff and drainage
derived from precipitation.
Stripping: The coarse initial separation of petroleum compounds into higher and lower
boiling point molecules.
Sub-bituminous
coal: A black coal intermediate in rank between lignite and bitumious coal, having
more carbon and less water than lignite.
Thermal
cracking: A hydrocarbon cracking process employing heat instead of catalysts to
facilitate the splitting of molecules.
Topping: Refers to distillation of crude petroleum to remove the lighter weight
molecules.
TSDF: Treatment, Storage and Disposal Facility
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Glossary
TSS: Total Suspended Solids
SCS: U.S. Soil Conservation Service
SIPS: State Implementation Plans
SNG: Synthetic Natural Gas
SDWA: Safe Drinking Water Act
USFWS: U.S. Fish and Wildlife Service
UST: Undergound Storage Tank
VOC: Volatile Organic Compounds
Wet scrubbers: Pollution control devices that generally remove particles from flue gas by
impacting them with water droplets. Such devices are typically installed in
sequence with electro-static precipitators and bag-houses.
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Introduction
1. INTRODUCTION
The National Environmental Policy Act of 1969 (NEPA) is the basic national charter for the
protection of the environment. In broad and far reaching provisions, it states the need for the
United States to prevent environmental damage and ensure that decision makers in federal
agencies consider the environmental consequences of their actions.
The U.S. Environmental Protection Agency (EPA) established regulations to govern its
compliance with NEPA in 40 CFR Part 6. Subparts A-F of Part 6 require EPA to undertake
environmental review procedures before a National Pollutant Discharge Elimination System
(NPDES) discharge permit is granted for a new source. A new source can be any new facility
(whether newly constructed or not) seeking a NPDES permit from EPA for which the discharge
is subject to effluent limitation guidelines and standards that EPA has promulgated for specific
industrial categories. Where individual states have been delegated authority to issue NPDES
permits, NEPA does not apply because there is no federal decision-making on individual
permits.
EPA's "Environmental Review Procedures for the New Source NPDES Program" (40 CFR
Part 6, Subpart F) instructs the responsible EPA official to evaluate first if a facility is a new
source and then, if it is a new source, to evaluate environmental information to determine if
significant impacts are likely to occur. Some of the environmental information to be evaluated
is typically provided by the NPDES permit applicant in the form of an environmental
information document (EID).
To assist EPA staff and, in turn, the NPDES discharge permit applicants, EPA's Office of
Federal Activities has issued a series of guidelines for EPA for use in determining the scope and
contents of EIDs on new source NPDES permits for specific industries and facilities. The
guidelines also assist EPA staff in reviewing and commenting on applicants' EID information.
The particular industries targeted in these guidelines are new source petroleum refineries and
coal gasification facilities.
An applicant's EID is used, along with EPA derived data, to evaluate if there are any
significant impacts of the proposed project. If no significant impacts are anticipated, EPA issues
a Finding of No Significant Impact (FONSI) for the granting of the NPDES permit. If one or
more significant impacts are identified, an environmental impact statement (EIS) must be
prepared by EPA.
The quality of an applicant's EID or EPA's EIS and the time it takes to develop the
documents is directly related to the quality of the information requested of the applicant by EPA
and, in turn, the quality of the data and analyses delivered by the applicant. Preparation of the
EID provides the applicant with an opportunity to identify all the potential impacts of his project/
The applicant should be working to find design modifications/siting solutions to any potential
impacts identified in developing and analyzing the EID data. Project planning, feasibility, and
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Introduction
design studies should provide the first identification of potential impacts, with the development
of the EID providing a more comprehensive identification of impacts.
The project the applicant presents to EPA in the permit application and EID should reflect
the applicant's best attempt to find the least environmentally damaging alternative(s), with
mitigation measures for residual impacts and alternatives, if necessary. If mitigation is
necessary, the applicant must present a rationale for trading off greater damages to some
environmental attributes in exchange for reducing other impacts.
EPA has anticipated several audiences for these guidelines: EPA staff; NPDES discharge
permit applicants and their consultants (those preparing EID information for EPA); and local,
state, and foreign government environmental officials. Officials in states that have been
delegated NPDES authority may find these guidelines useful in their review of individual
permits. These guidelines were expressly prepared as background information for EPA staff to
assist them in preparing directives to applicants and as a reference to assist in evaluating
applicant/consultant prepared EIDs and EISs. All audiences should consider this document as
suggestions, not as law, regulation, or policy. These guidelines replace two separate documents
issued previously (EPA-130/6-81-001, EPA-130/6-80-001).
Organization of These Guidelines
These guidelines consist of three major parts:
• A regulatory overview that briefly describes NEPA, the Clean Water Act under which
the NPDES permit is gran ted i and other relevant laws, regulations, and executive orders
that provide the regulatory context for the guidelines.
• A technology overview that covers the processes and pollution control activities that are
used in petroleum refining and coal gasification.
• An environmental documentation part that follows the order of a typical EIS. This part
focuses on what information to ask for and to look for in new source EIDs and EISs.
Emphasis is on identifying data, data assessment, methodologies, and qualitative and
quantitative approaches for identifying the occurrence, magnitude, and significance of
specific impacts.
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Regulatory Overview
2. REGULATORY OVERVIEW
This section presents information on the major federal environmental statutes. Four are
covered in detail: The National Environmental Policy Act, the Clean Water Act, the Clean Air
Act, and the Resource Conservation and Recovery Act. Additional statutes are briefly
summarized at the end of the section.
National Environmental Policy Act
EPA's responsibility to protect the environment in the decisions it makes is governed by
law,1 regulations applied to all federal agencies,2 and EPA's-own NEPA regulations.3 EPA's
NEPA regulations specifically state that NEPA and its implementing regulations require "that
Federal agencies include in their decision making processes, appropriate and careful
consideration of all environmental effects of proposed actions, analyze potential environment
effects of proposed actions and their alternatives for public understanding and scrutiny, avoid
or minimize adverse effects of proposed actions, and restore and enhance environmental quality
as much as possible." (40 CFR Part 6.100).
EPA and CEQ regulations call for the initiation of NEPA reviews as early as possible in
project planning. In the specific case of petroleum refineries and coal gasification facilities,
EPA must prepare environmental documentation on the NPDES permits it grants for the
discharge of wastewater. The determination of a "new source" is made by the EPA Region in
accordance with NPDES permit regulations under 40 CFR Parts 122.21(1) and 122.9(a) and (b).
A "new source" may be defined as any facility newly constructed, or a discharge from a process
or equipment that totally replaces the discharge of pollutants at an existing source, and the
operator of the facility is seeking a NPDES permit from EPA for which the discharge is subject
to effluent limitations guidelines for new sources. The permit applicant must provide facility
and environmental data with the NPDES application, analyze environmental effects, and provide
EPA with an environmental information document (EID).
In accordance with EPA NEPA procedures, the nature and extent of information required
from applicants as part of the EID is bounded by two separate agreements:
• EIDS must be of sufficient scope to enable EPA to prepare its environmental assessment.
• In determining the scope of the EID, EPA must consider the size of the new source and
the extent to which the applicant is capable of providing the required information. EPA
must not require the applicant to gather data or perform analyses which unnecessarily
duplicate either existing data or the results of existing analyses available to EPA. EPA
'NEPA, 42 USC sections 4321-4370a.
240 CFR 1500-1508.
J40 CFR Part 6.
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Regulatory Overview
must also keep requests for data to the minimum consistent with the Agency's
responsibilities under NEPA.
The EPA procedures.call for EPA to consult with the applicant to determine the scope of
the EID at the outset of the process. Scoping should begin as soon as EPA is presented with
the proposal.
Two other important points in the CEQ Regulations include the use of an interdisciplinary
approach that insures the "... integrated use of natural and social sciences and the environmental
design arts..." (40 CFR Part 1502.6) and the necessity that EISs be written in plain language
so the "... decision makers and the public can readily understand them ..." (40 CFR Pan
1502.8).
The NEPA Process
Once EPA has sufficient data from the applicant and other sources, a written environmental
assessment (EA) is prepared that indicates whether the potential exists for significant adverse
impacts from the project, and whether such impacts can be reduced to less-than-significant levels
through project redesign or mitigation measures. Where significant impacts can be avoided,
EPA can issue the NPDES permit, the EA, and a finding of no significant impact (FONSI).
Where environmental impacts cannot be made insignificant, an EIS must be prepared. The
lead agency supervises the preparation of the EIS if more than one federal agency is involved
in the same action, or the proposed action is related to activities of other agencies. When more
than one agency has a direct interest in the proposed activity, the lead agency will seek the
cooperation of agencies through memoranda of understanding (MOUs). The environmental
analyses from the cooperating agencies are used to the maximum extent possible consistent with
the responsibility of the lead agency. In the case of new source NPDES permits, EPA is the
lead agency and publishes a Federal Register Notice of Intent (NOI) announcing its intention to
prepare an EIS. The notice requests suggestions on the contents of the EIS. Possible
alternatives, impacts, mitigation measures, and study design changes are often recommended.
For new source petroleum refineries and coal gasification facilities, EPA staff may: •
• Prepare the EIS;
• Engage a knowledgeable consultant to prepare the EIS for EPA under the Agency's
direction; or
• Enter into a three-party agreement where EPA directs a consulting firm in the preparation
of the EIS, with the applicant funding the consultant.
Data for the EIS comes from the applicant's application, supporting materials, and EID and
other sources. When a third party agreement is in effect, the applicant does not prepare an EID,
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Regulatory Overview
but provides the same information as input to the EIS. Independent analysis or confirmation of
applicant data provides EPA with reassurances that the EIS can draw supportable conclusions.
EPA takes full responsibility for the scope and contents of the EIS whether it is prepared by
EPA staff or a consultant.
Once the document is completed and approved by EPA, the Draft EIS is circulated for
public review by the general public and other federal, state, and local agencies. Written
comments on the draft EIS and those questions and comments recorded during public hearing(s)
are collected by EPA and responded to by EPA staff or the EIS consultant. Information to
respond to some questions or comments may require information from the applicant or
reconsideration of some feature or mitigation measure of the project. The written responses to
questions and comments, any minor project modification or- new mitigation measures, and an
incorporation by reference of the Draft EIS are collated into a Final EIS. The Final EIS is
distributed to all those individuals and entities commenting on the Draft EIS.
A record of decision (ROD), a public record documenting EPA's decision-making process,
is issued at the time of the NPDES permit issuance. The ROD lists any mitigation measures
necessary to make the recommended alternative more environmentally acceptable. Such
mitigation is made a condition of the permit.
The Clean Water Act
The primary goal of the Clean Water Act (33 U.S.C. 125 et seq.) is to "restore and maintain
the chemical, physical, and biological integrity of the Nation's water." The Act covers all
pollutant discharges to all waters of the United States. Permits issued under the NPDES
program, Clean Water Act section 402, serve as the means to achieve this goal.
The NPDES permit program is implemented by 39 states, and where a state is not delegated
authority for the program, NPDES permits are issued by the responsible EPA regional office.
A NPDES Permit is required prior to the discharge of any pollutant from a point source into
waters of the United States. Point sources are discharges of process water and/or stormwater
runoff associated with industrial activity from any discrete conveyance including pipes, ditches,
and swales.
Process Water
A NPDES permit contains specific limits on concentrations or loadings of pollutants in
discharges. Pollutant discharge limits for process water are set Using one or more methods.
"Technology-based" limits are set using guidelines developed for particular industrial categories
and their common pollutants. Discharges may also be controlled by "water quality-based"
limits. Water quality-based limits are set using state ambient water quality standards and the
expected dilution of pollutants in the receiving water. Limitations are developed to ensure that
the concentration of a pollutant caused by a discharge would not cause an exceedance of a water
quality standard in the receiving water. Water quality-based limits may be more restrictive than
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Regulatory Overview
technology-based limits, in which case water quality-based limits are those imposed. In the
absence of specific technology-specific limitations and water quality-based limitations, however,
permit writers may use Best Professional Judgment (BPJ) to ensure that impacts of a discharge
on receiving waters are minimized.
Application to the Petroleum Refining Industry
Petroleum refining is one of the 34 industrial categories for which technology-based effluent
limitation guidelines have been established by EPA (40 CFR Part 419).
Within the effluent guidelines, EPA has set,New Source Performance Standards (NSPS),
Pretreatment Standards, and contaminated runoff standards for the following categories at new
source petroleum refining facilities: topping, cracking, petrochemical, lube and integrated.
The NSPS apply to point sources discharging directly to waters of the United States. The
Pretreatment Standards apply only to those point sources discharging to publicly-owned treatment
works (POTWs), and are intended to prevent pollutants from reaching POTWs in amounts that
would injure workers, pass through treatment plants, interfere with treatment processes, or
contaminate sludge. The PSNS are self-implementing, and are thus enforceable even without
being written into permits. Discharge limitations addressing the same pollutants covered by the
PSNS may be incorporated into permits as long as they are at least as stringent as the PSNS.
Stormwater guidelines define contaminated runoff as stormwater runoff contacting "any raw
material, intermediate product, finished product, byproduct or waste product located on
petroleum refinery property." Facilities discharging to POTWs are not subject to the NEPA
process, therefore, EA/FONSI and EISs are not necessary, nor is the applicant required to
submit an EID.
Application to the Coal Gasification Industry
Coal gasification is not one of the 34 industrial categories for which EPA has published
specific technology-based effluent limitation guidelines. But the industry may fit (at the
discretion of the state permitting agency or EPA Regional office) into one or more categories
including coal preparation plants and associated areas, particularly with regard to coal pile
runoff. Generally, coal gasification facilities have limited process discharges to receiving
waters, and those that do occur are primarily non-contact cooling waters.
Stormwater
Stormwater runoff is regulated under the NPDES program at 40 CFR Parts 122, 123, and
124. In 1990, EPA issued regulations to address currently unpermitted discharges of stormwater
associated with industrial activity. These stormwater regulations are intended to reduce or
eliminate pollutants in discharges from large construction sites and industrial facilities. To ease
implementation of these regulations, EPA has issued construction and industrial general permits
under which eligible permittees are required to develop and implement stormwater pollution
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Regulatory Overview
prevention plans. These plans must incorporate BMPs that control stormwater discharges and
limit stormwater contact with pollutants. The stormwater regulations also allow permitting
authorities to issue individual stormwater NPDES permits for discharges on a case-by-case basis.
Application to the Petroleum Refining Industry
Generally, individual permits issued to new source petroleum refineries contain effluent
limits for process wastewater and stormwater discharges. In addition to the stormwater
discharge limits specified for each refinery outfall, facility-specific best management practices
are specified to control stormwater runoff and minimize the contact of stormwater with
pollutants. Because petroleum refining facilities are subject to stormwater effluent limitation
guidelines at 40 CFR Part 419, such facilities are not eligible for coverage under EPA's general
permits for stormwater.
Application to the Coal Gasification Industry
Coal gasification facilities are subject to NPDES stormwater permit application requirements
at 40 CFR Part 122.26(b)(14)(vii) if any gasification products are used on-site to generate
power, even if only for in-plant processes.
If power is not generated at a facility, then it is regulated only if it discharges pollutants to
stormwater in excess of amounts defined by EPA as Reportable Quantities. Reportable
Quantities of pollutants are listed in 40 CFR Parts 117 and 302.
All regulated facilities that discharge to waters of the United States must apply for
stormwater permits. Most facilities opt for coverage under EPA's general permits, as they allow
permittees more flexibility in choosing BMPs than individual permits.
In addition to the requirement to implement a stormwater pollution prevention plan, general
permits for coal gasification facilities have discharge limits set for total suspended solids (TSS)
and pH for coal pile runoff. The limit for TSS is SO mg/1, and pH must be no less than 6.0 and
no greater than 9.0. The requirement for TSS is waived if the facility has a stormwater
containment structure designed to hold runoff from a 10-year, 24-hour storm event.
Application to Construction Activity
The construction activities (including clearing, grading and excavation) involved in building
either petroleum refineries or coal gasification facilities are regulated by EPA's stormwater rules
if they disturb 5 or more total acres of land, a relatively small area for either type of facility.
For construction sites, emphasis is placed on minimizing the erosion and sedimentation effects
of stormwater runoff, in addition to minimizing contact with pollutants. Details of the pollution
prevention plan requirements for construction sites, including soil stabilization practices,
diversion structures, and sediment basins can be found in the Construction Permit Language and
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Regulatory Overview
the Construction Fact Sheet of the September 9, 1992 Federal Register (Vol. 57, No. 175), and
the September 15, 1992 Federal Register (Vol. 57, No. 187).
The Resource Conservation and Recovery Act
The Solid Waste Disposal Act (SWDA) of 1965 and major amendments of the Resource
Conservation and Recovery Act (RCRA) of 1976 and the Hazardous and Solid Waste
Amendments (HSWA) of 1984 comprise the principal federal law mandating regulation of both
solid and hazardous waste. Collectively referred to as RCRA, the law consists of three basic
parts: Subtitle D, which encourages states to develop plans for controlling their non-hazardous
solid waste, Subtitle I, which applies to underground storage tanks (USTs), and Subtitle C,
which mandates a system to regulate hazardous wastes from the time of their generation to the
time of their disposal. Because it has placed most of the burden of non-hazardous waste
regulation onto the states, RCRA is now synonymous with hazardous waste regulation. Once
a waste is determined to be hazardous, any generator, transporter or manager of such waste must
comply with the pertinent rules promulgated under Subtitle C.
A waste is regulated as hazardous if:
• It is not specifically excluded from regulation as a hazardous waste (40 CFR Pan 261.4)
AND
• Exhibits one of the hazardous characteristics detailed in 40 CFR Part 261 Subpart C
(ignitability, corrosivity, reactivity, or toxicity)
OR
• Is specifically listed as a hazardous waste (40 CFR Part 261, Subpart D).
The wastes excluded from regulation typically include wastes recycled in certain ways,
wastes regulated under separate statutes (such as the Clean Water Act), and particular wastes
from certain industries.
Non-hazardous Waste Requirements - Subtitle D
Subtitle D's provisions include minimum standards for protecting human health and the
environment at solid waste landfills and* technical guidance for states on establishing
environmentally-sound solid waste management plans. The specific regulatory controls on
non-hazardous waste depend on the requirements of state plans. For questions concerning
non-hazardous waste regulation in a particular state, a copy of the state's solid waste
management plan should be consulted.
Underground Storage Tank Requirements - Subtitle I
RCRA's requirements for underground storage tank systems apply to systems of 110-gallon
capacity or greater. The requirements include controls on the design, construction, and
installation of new underground storage tanks, and the upgrading of existing tanks. Provisions
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Regulatory Overview
cover general operating requirements as well as the detection, reporting, investigation, and
confirmation of releases. The regulations also address release response and corrective action
requirements for petroleum and hazardous substance-containing USTs at 40 CFR Parts 280.60
- 280.67. In general, the extensive costs and liabilities of operating an UST in compliance with
RCRA requirements have led to significant reductions in the number of new UST units and
removal from service of many older tanks. RCRA does not include similar requirements for
above ground tanks.
Hazardous Waste Requirements - Subtitle C
/
The hazardous waste regulations provide for a comprehensive "cradle to grave" system of
management and include rules governing waste disposed of on land, recycling, and generators,
and transport, storage, or disposal facilities (TSDFs). The applicability of these regulations is
generally uniform across industry, and is driven by the listing process. If a waste is hazardous,
it is subject to these regulations. Some industries, like petroleum refining, have specific wastes
listed as hazardous; others, such as coal gasification may have specific wastes listed as
non-hazardous.
Land Disposal Restrictions
The Hazardous and Solid Waste Amendments (HSWA) of 1984 (40 CFR Part 268) prohibits
the land disposal of any hazardous waste that does not meet certain treatment standards.
Treatment standards may be concentration-based (the most common) or technology-based (use
of the best demonstrated available technology [BOAT]). HSWA automatically prohibits the land
disposal of hazardous wastes if EPA fails to establish treatment standards for them by certain
statutory deadlines (see 40 CFR Parts 268.10 - 268.12). Wastes may be excluded from these
land disposal restrictions (LDR) under circumstances described at 40 CFR Part 268. l(c).
Recycling and Reuse Exemptions and Provisions
Under 40 CFR Part 261.2(e), certain recyclable materials are exempt from hazardous waste
regulation if they qualify as one of the following:
• Wastes used or reused as ingredients in production without first being reclaimed
/
• Wastes used or reused as substitutes for commercial products without first being
reclaimed
• Wastes returned to the original process that generated them without first being reclaimed.
RCRA also contains standards at 40 CFR Part 266 concerning the land application of
recyclable materials derived from hazardous waste, the burning of hazardous waste for energy
recovery, and the burning of hazardous waste in boilers and industrial furnaces.
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Regulatory Overview
Hazardous Waste Generators
All generators of waste are required to determine if the waste is hazardous and, in most
cases, determine the amount generated in each calendar month. Requirements for generators
vary according to the amount of waste produced, with small quantity generators subject to the
least stringent controls.
Medium and large quantity generators are facilities that generate between 100 -1,000 kg and
greater than 1,000 kg of hazardous waste per month, respectively. They have similar types of
requirements, although some requirements are more strict for large quantity generators.
Medium and large quantity generators having waste transported off-site must certify that they
have a waste minimization program in place to reduce the amount and/or toxicity of the
hazardous waste generated prior shipment to a transport, storage, or disposal facility (TSDF).
Medium and large quantity generators may accumulate hazardous waste on site without
obtaining a TSDF permit provided they comply with the regulations regarding quantity limits,
time constraints, and technical storage standards for on-site accumulation, and requirements for
personnel training, emergency procedures, and preparedness and prevention of accidents and
spills (see 40 CFR Part 262.34).
Hazardous Waste Treatment, Storage, and Disposal Facilities
As with transporters, hazardous waste management facilities must obtain a permit before
beginning operations. Under such permits, TSDFs must comply with the following
requirements:
• General waste handling requirements — personnel training, waste analysis prior to
management, location standards (fault zones and flood plains)
• Preparedness and Prevention
• Contingency plans and emergency procedures.
Ground Water Monitoring
In addition to the TSDF requirements outlined above, HSWA of 1984 added certain
minimum technical requirements (MTRs) for the construction of hazardous waste management
facilities. AH new facilities completed after HSWA's enactment must have, at a minimum,
double liners and leachate detection and control systems in place. Retrofitting of most facilities
existing at the time of HSWA's enactment was to have been finished in 1988. Any waste
exempt from the land disposal restrictions of HSWA must still go to a MTR-equipped facility
for its disposal or management.
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Regulatory Overview
Under Parts 264 and 265, RCRA also specifies more detailed operating parameters for the
following:4
container storage units surface impoundments
tank systems waste piles
land treatment underground injection wells
incinerators ' thermal treatment units
landfills chemical, physical, biological treatment units
drip pads
Application to the Petroleum Refining Industry
While the majority of RCRA's hazardous waste regulations apply generally to all facilities
and wastes, certain provisions and controls address specific industries. Several listed hazardous
wastes are from petroleum refining operations. Several other hazardous wastes listed from
non-specific sources could also be generated by petroleum refineries. Listed wastes from
refineries include the following:1
K048 - Dissolved air flotation (DAF) floats
K049 - Slop oil emulsion solids
K050 - Heat exchanger bundle cleaning sludge
K051 - API separator sludge
K052 - Tank bottoms (leaded).
f
Hazardous wastes from non-specific sources, potentially from petroleum refineries, include
the following:6
• F024 - Process wastes7
• F025 - Condensed light ends, spent filters and filter aids, and spent desiccant wastes7
• F037 - Primary oil/water/solids separation sludge
• F038 - Secondary (emulsified) oil/water/solids separation sludge
• F039 - Leachate resulting from disposal of more than one hazardous waste.
Many organic chemical wastes may be generated by petroleum refineries. Wastes not
excluded at 40 CFR Part 261.4 may still be hazardous if they exhibit a hazardous characteristic.
'Standards for these processes are specified only for interim status facilities (40 CFR Part 265).
These wastes are defined under the petroleum refinery sub-category of Part 261.32 (the K list).
These wastes are defined at 40 CFR Part 261.31 (the F list).
'From the production of certain chlorinated aliphatic compounds by free radical catalyzed processes.
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Regulatory Overview
Application to the Coal Gasification Industry
The coal gasification industry is not addressed specifically by rules promulgated under
RCRA. However, certain wastes that are generated at coal gasification facilities are excluded
from coverage under hazardous waste regulations. Fly ash waste, bottom ash waste, slag waste,
and flue gas emission control waste are all exempt from regulation if they are derived from the
combustion of coal or other fossil fuel. Other coal gasification wastes may be ruled hazardous
if they are specifically listed or exhibit one of the four hazardous characteristics.
For further guidance on the specifics and applicability of RCRA, consult:
Wagner, Travis, P., The Complete Guide to the Hazardous Waste Regulations. Second
edition, Van Nostrand Reinhold, New York, New York, 1991.
The Clean Air Act
The Clean Air Act, originally passed in 1967, and amended as recently as November 1990,
is the primary law protecting the Nation's air quality from pollutant emissions. The Act requires
EPA to promulgate a set of air quality standards, whose achievement is the overall objective of
the Act. These National Ambient Air Quality Standards (NAAQS) were established for ozone,
carbon monoxide, particulates, sulfur dioxide, nitrogen dioxide, and lead. To achieve these
standards, the Act requires states to develop State Implementation Plans (SIPs) which combine
region-specific compliance strategies with enforceable emissions control requirements.
While the November IS, 1990 amendments make significant changes to the Clean Air Act,
these changes are to be phased in over a number of years. Because of this transition period, it
is necessary to describe the Act as it stands now, as well as new provisions and when they will
take effect.
Current Clean Air Act Requirements
There are three major existing requirements under the Clean Air Act. These are New
Source Reviews, New Source Performance Standards, and National Emissions Standards for
Hazardous Air Pollutants. Each of these is explained briefly below.
New Source Review
Newly constructed.industrial facilities and expansions of existing facilities that result in
increased emissions are subject to a New Source Review. The requirements of this review vary
depending on whether or not air quality standards have been attained in the area the site is
located.
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Regulatory Overview
In areas already meeting air quality standards, rules are designed to prevent new sources
from preventing significant deterioration (PSD) of air quality. The general requirements under
these circumstances are:
• Compliance is necessary only for new major sources (potential emissions of any regulated
pollutant exceeding either 100 or 250 tons per year, depending on the source's industrial
category) and major modifications to such sources (defined as 40 tons per year for sulfur
dioxide [SOJ, nitrogen oxides [NOJ, or volatile organic compounds [VOCs]).
• Construction of new sources cannot begin until a permit has been issued.
\
• Best Available Control Technology (BACT) must be used. BACT is identified by EPA
on a case-by-case basis as the best state-of-the-art control technology that could be used.
The applicant must justify any departures from this technology.
• After BACT requirements are satisfied, any residual emissions must be accounted for by
an available "increment" of air quality deterioration.
The restrictions are more severe in areas that have not attained the ambient air quality
standards. These requirements are outlined below:
• Compliance is necessary only for new major sources (potential emissions exceeding 100
tons per year of particulates, SQ, NO,, VOCs, or carbon monoxide [CO]) and major
modifications.
• Lowest Achievable Emission Rate technology (LAER) must be used. This technology
must be the most stringent control technology available.
• Any residual emissions after installation of LAER must be "offset" by emissions
reductions at other sources which must exceed the reductions expected from the
application of LAER technology.
PSD and non-attainment requirements are applied to each regulated pollutant separately. It
is thus possible for a new source to be required to meet non-attainment "offset" requirements
for one pollutant, while having to meet PSD "increment" requirements for another.
New Source Performance Standards (NSPS)
Emissions limitations have been established for certain pollutants from new sources. Under
the current regulations, sources subject only to NSPS are not necessarily required to obtain a
permit. However, the NSPSs are self-implementing, meaning new sources are automatically
subject to their requirements.
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Regulatory Overview
The performance standards for new source petroleum refineries address the following areas
(40 CFR Part 60, subpart J):
• Paniculate matter and carbon monoxide from fluid catalytic cracking unit catalyst
regenerators
• Sulfur oxides.
Coal gasification is not an industrial category for which EPA has established NSPS. Coal
gasification facilities which generate steam from the combustion of coal do have NSPS as
fossil-fuel-fired steam generators. The performance standards for this category address
paniculate matter, sulfur dioxide and nitrogen oxides.
National Emissions Standards for Hazardous Air Pollutants (NESHAPs)
The 1970 Clean Air Act authorized EPA to set special standards for hazardous air pollutants.
EPA has established NESHAPs for 7 substances: arsenic, asbestos, benzene, beryllium,
mercury, radionuclides, and vinyl chloride (see 40 CFR Part 61).
Changes to Take Effect as 1990 Amendments Are Phased in
Several new or more stringent requirements will come into effect as the 1990 Amendments
to the Clean Air Act are implemented. The most significant changes relate to a new
federal-level permit program and overhaul of the air toxics program. New provisions are
described briefly below.
Federal Permit Program
The new Amendments place much greater emphasis on federal control than the current
SIP-dependent Act. ' They require virtually all significant sources of air emissions to obtain
permits. SIP requirements are often applied genetically, permitting an array of industrial
operations to take place as long as appropriate pollution controls are installed. The permit
program will be much more specific, defining applicable emissions limits for each individual
source. Any operational change that increases emissions above specified limits will probably
necessitate permit modifications.
New Source Review
Smaller sources and modifications will become subject to New Source Review requirements.
A change causing any increase in emissions will be considered a modification in extreme
non-attainment areas, and 25 tons per year will be considered a major source in serious and
severe non-attainment areas.
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Regulatory Overview
Non-attainment Offsets
In an effort to reduce the number and severity of ozone non-attainment areas, the ratio
between the residual emissions still escaping after LAER technology is installed and the decrease
in emissions elsewhere required to offset them will be significantly increased for VOCs. In
addition, NO, will generally be subject to offset requirements.
New Source Performance Standards (NSPS)
Permits will be required for all new sources that are subject only to NSPS. Permits must
be obtained before any construction can begin.
NESHAPS
The air toxics program has been completely redone. There is now a list of 189 hazardous
air pollutants that are to be regulated. The strategy of regulation has been changed from a
substance-specific numerical approach, to one relying on the use of Maximum Achievable
Control Technology (MACT).
Other Relevant Requirements
There are several acts and executive orders that are significant in the review of NEPA
documentation. The provisions of the most important acts are outlined below.
Clean Water Act Section 404 Permits
Clean Water Act Section 404 requires a permit from the U.S. Army Corps of Engineers
(USCOE) for the placement of material, whether dredged or fill, into waters of the US. The
404 permit also pertains to activities in wetlands and riparian areas. Before being issued a
Section 404 permit, an applicant must obtain a Clean Water Act Section 401 certification from
the EPA (or the state agency delegated NPDES Authority), which states that any discharge
complies with all applicable effluent limitations and water quality standards. Exemptions to
Section 404 are listed in Section- 404(r) which refers to federal projects specifically authorized
by Congress if information on the effects of such discharge is included in an EIS.
If the state in which the new source coal gasification or petroleum refining facility is to be
built has been delegated 404 permit authority, then, as with the NPDES Program, the issuance
of the 404 permit is not a federal action, and is not subject to NEPA requirements. If the state
has neither NPDES nor 404 permit authority, then the issuance of both types of permits is done
by a federal agency and is thus subject to environmental review under NEPA. In this instance,
CEQ regulations at 40 CFR 1501.5 require that a lead agency by designated to conduct a single
environmental review associated with the issuance of all permits for the facility. Regardless
which agency is leading the review, neither the NPDES permit nor the 404 permit may be issued
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Regulatory Overview
before the review process is completed and its results (either a FONSI or a final EIS) published
in the Federal Register.
Endangered Species Act
Established in 1973, the Endangered Species Act (16 U.S.C. 1531-1544; P.L. 93-205)
provides a means whereby the ecosystems supporting threatened or endangered species may be
conserved and provides a program for the conservation of such species. The Act requires that
all federal departments and agencies seek to conserve endangered and threatened species and
cooperate with state and local agencies to resolve water resource issues in concert with
conservation of endangered species.
Section 7 of this Act requires federal agencies to ensure that all federally associated activities
within the United States do not have adverse impacts on the continued existence of threatened
or endangered species or on designated areas (critical habitats) that are important in conserving
those species. Agencies undertaking a federal action must consult with the U.S. Fish and
Wildlife Service (USFWS), which maintains current lists of species that have been designated
as threatened or endangered, to determine the potential impacts a project may have on protected
species. The National Marine Fisheries Service undertakes the consultation function for marine
and anadromous fish species while USFWS is responsible for terrestrial, wetland, and fresh
water species.
The USFWS has established a system of informal and formal consultation procedures, and
the results of informal or formal consultations with the USFWS under Section 7 of the Act
should be described and documented in the EID/EIS. Sections of an EID/EIS that should
include endangered and threatened species information are the Project Alternatives and the
Affected Environment sections. If a threatened or endangered species may be located within the
project area and may be affected by the project, a detailed endangered species assessment
(Biological Assessment) may be prepared independently or concurrently with the EIS and
included as an appendix to the EID/EIS.
National Historic Preservation Act
The National Historic Preservation Act of 1966 (16 U.S.C. 470 et set]., P.L. 89-665) as
amended (P.L. 95-515) establishes federal programs to further the efforts of private agencies and
individuals in preserving the historical and cultural foundations of the nation. This Act authorizes
the establishment of the National Register of Historical Places. It establishes an Advisory
Council on Historic Preservation authorized to review and comment upon activities licensed by
the federal government that have an effect upon sites listed on the National Register of Historic
Places or that are eligible to be listed. The Act also sets up a National Trust Fund to administer
grants for historic preservation. The Act also authorizes regulations addressing State historical
preservation programs. State preservation programs can be approved where they meet minimum
specified criteria. Additionally, Native American tribes may assume the functions of State
Historical Preservation Officers over tribal lands where the tribes meet minimum requirements.
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Regulatory Overview
Under the Act, federal agencies assume the responsibility for preserving historical properties
owned or controlled by the agencies.
Section 106 of the NHPA requires that every federal agency "take into account" how each
of its undertakings could affect historic properties. Historic properties are any properties
included or eligible for listing in the National Register of Historic Places. The issuance of a
NPDES permit constitutes an "undertaking" under the Act. When an undertaking affects an
historic property, comments of the Advisory Council regarding the action must be sought. The
federal agency involved is responsible for initiating and completing the Section 106 review
process.
A series of amendments to the National .Historic Preservation Act in 1980 contain
codification of portions of Executive Order 11S93 (Protection and Enhancement of the Cultural
Environment -16 USC 470). These amendments require an inventory of federal resources and
federal agency programs to protect historic resources and authorize federal agencies to charge
federal permittees and licensees reasonable costs for protection activities.
Where activities involve a proposed federal action or federally assisted undertaking, or
require a license from a federal or independent agency, and such activities affect any district,
site, building, structure, or object that is included in or eligible for inclusion in the National
Register, the agency or licenses must afford the Advisory Council on Historic Preservation a
reasonable opportunity to comment with regard to the undertaking. Such agencies or licensees
are also obligated to consult with State and Native American Historic Preservation Officers
responsible for implementing approved State programs.
It should be noted that regulations codified at 40 CFR Part 6.605(b)(4) provide that Issuance
of a new source NPDES permit that will have "significant direct and adverse effect on a
property listed in or eligible for listing in the National Register of Historic Places" triggers the
preparation of an EIS.
Coastal Zone Management Act
The1 Coastal Zone Management Act's (15 CFR 930, P.L. 92-583) purpose is "to preserve,
protect, develop, and where possible, restore or enhance, the resources of the Nation's coastal
zone for this and future generations." To perform this goal, the Act provides for financial and
technical assistance and federal guidance to states and territories for the conservation and
management of coastal resources.
States are encouraged, but not required, by the Act to develop a coastal zone management
program considering such things as ecological, cultural, historic, and aesthetic values as well as
economic development needs. Section 307(c) of the Act prohibits the USEPA from issuing a
permit for any activity affecting land or water use in the coastal zone until the applicant certifies
that the proposed activity complies with the state Coastal Zone Management program, and the
state or its designated agency concurs with the certification.
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Regulatory Overview
Executive Orders 11988 and 11990
Executive Order 11988 (Floodplain Management) of 1977 requires each federal agency to
"... avoid to the extent possible the long- and short-term adverse impacts associated with the
occupancy and modification of floodplains and to avoid direct and indirect support of floodplain
development wherever there is a practicable alternative..." within the 100-year flood elevation.
For an EID/EIS, this requires that alternatives to avoid development in a floodplain be
considered. If development requires siting in a floodplain, action shall be taken to modify or
design the facility in a way to avoid damage by floods.
Executive Order 11990 (Protection of Wetlands) of 1977 is similar to E.O. 11988 in that
it requires each federal agency to "...avoid to the extent possible the long- and short-term
adverse impacts associated with the destruction or modification of wetlands and to avoid direct
or indirect support of new construction in wetlands wherever there is a practicable alternative..."
When constructing a new facility, actions that minimize the destruction, loss, or degradation of
wetlands, and actions to preserve and enhance the natural and beneficial values of wetlands are
required. If there is no practicable alternative to wetland construction projects, proposed action
must include measures to minimize harm! Construction in wetlands also falls under Section 404
of the Clean Water Act administered by the U.S. Army Corps of Engineers.
Executive Order 12898 (Environmental Justice)
During the past decade, it has become apparent that environmental impacts do not affect all
people equally. Studies by the U.S. General Accounting Office, the United Church of Christ,
community leaders, and academics has brought attention to the inequitable exposure to
environmental hazards that some ethnic and lower income communities face.8 In recognition
of environmental justice issues and for fair treatment for all socio-economic classes, the
President directed each federal agency in Executive Order 12898 to "develop an agency-wide
environmental justice strategy . . . that identifies and addresses disproportionately high and
adverse human health or environmental effects of its programs, policies, and activities on
minority populations and low-income populations."
Due to its requirements for .social impact analysis and public participation, NEPA can be
used by federal agencies to integrate the principles of environmental justice into agency missions
and actions. The greatest level of legal vulnerability for the "lead agency" is created not by
taking actions that will create negative impacts, but by failing to consider or possibly analyze
those impacts in an EIS that treats them with full, good-faith consideration. While the term
•U.S. General Accounting Office, Siting of Hazardous Waste Landfills and Their Correlation with Racial and
Economic Status of Surrounding Communities. GAO/RCED-83-168, June 1, 1983. Commission for Racial Justice.
United Church of Christ, Toxic Waste and Race in the United States: A National Report on the Racial and Socio-
Economic Characteristics of Communities with Hazardous Waste Sites, New York, 1987. Holmes Ralston III,
Environmental Ethics, Temple University Press: Philadelphia, PA 1988. Peter S. Wenz, Environmental Justice,
State of New York Press: Albany. NY. 1988.
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Regulatory Overview
"environmental justice" has not been formally defined, the general principle is for all segments
of the population, whatever race, ethnicity, or income, be treated fairly with respect to the
development, implementation, and enforcement of environmental laws, regulations, and policies.
Farmland Protection Policy Act
•
Under the Farmland Protection Policy Act of 1980 (P.L. 97-98), the U.S. Soil Conservation
Service (SCS) is required to be contacted and asked to identify whether a proposed facility will'
affect any lands classified as prime' and unique farmlands.
Rivers and Harbors Act
Section 10 of the Rivers and Harbors Act of 1899 (33 U.S.C. 401-413; 33 CFR 322)
prohibits the unauthorized obstruction or alteration of any navigable waters of the United States.
Under Section 10 of this Act, a permit is required from the U.S. Army Corps of Engineers for
the construction of any structure in or over navigable waters of the United States. Section 10
is usually combined with Section 404 of the Clean Water Act, which covers the discharges of
fill to all waters of the United States (as opposed to Section 10, which covers only navigable
waters).
Wild and Scenic Rivers Act
The Wild and Scenic Rivers Act of 1968 (P.L. 90-542, 16 U.S.C. 1273 et seq.) ensures that
"... Certain selected rivers...shall be preserved in a free flowing condition, and that they and
their immediate environments shall be protected for the benefit and enjoyment of present and
future generations." The Act, in Section 7, prohibits the issuance of a license for construction
of any water resources project that would have a direct, adverse effect (stop free-flowing
conditions or affect their local environments) on the rivers of the United States selected as
possessing remarkable scenic, recreational, geologic, fish and wildlife, historic, cultural, or other
similar values.
The National Rivers Inventory has selected rivers and streams placed by acts of Congress,
while other rivers and streams have been proposed to be included in the inventory. During
project planning and project impacts identification for an EID/EIS, these rivers and streams must
be considered and the findings should be noted in a Wild and Scenic Rivers Act summary.
While there is no legal requirement to consider state-listed wild and scenic rivers and streams
or unique areas during project planning or in an EID/EIS, it is recommended that any impacts
to such areas be considered and addressed as with the federal Wild and Scenic Rivers Act
requirements.
Fish and Wildlife Coordination Act
Enacted in 1934, the Fish and Wildlife Coordination Act (16 U.S.C. 661 et seq., P.L.
85-624) authorizes the Secretary of Interior to provide assistance to, and cooperate with, federal,
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Regulatory Overview
state, and public or private agencies and organizations in the development, protection, rearing,
and stocking of all species of wildlife, resources thereof, and their habitat. The majority of the
Act is associated with the coordination of wildlife conservation and other features of
water-resource development programs. The EID/EIS should include a Fish and Wildlife
Coordination Act report which includes all coordination efforts in the planning process of the
project with the Act, and recommendations of the USFWS must be summarized in the EID/EIS,
.usually as part of the Consultation and Coordination section.
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Technology Overview
3. TECHNOLOGY OVERVIEW
Petroleum Refining
Petroleum refining is the processing of crude oil into a multitude of products. Crude oil
characteristics vary with their sources, and refineries are often designed to process only crude
oil from a particular source. Refineries also differ widely in capacity and in the combination'
of processes and products produced. Some may be able to produce a wide range of items such
as fuel gas, liquified petroleum gases (LPG), gasoline, olefins, greases, asphalt, and coke.
Other simpler refinery operations may produce only fuel gas, gasoline blending stocks, or heavy
fuel oil.
In general, refinery crude oil processing is based on the fact that crude oil consists of a large
number of separate organic compounds whose properties are primarily dependent on the number
of carbon atoms they contain. Increasing numbers of carbon atoms result in higher boiling
points, and the first step in the refining process is to separate the crude by distillation into
several fractions according to boiling point. The lowest temperature boiling fraction, a gas at
normal conditions, consists of methane, having a single carbon atom, and other molecules
ranging from 2 to 4 carbon atoms. These components of the first, or gas, fraction are used as
fuel gas, LPG (mainly propane and butane), and as building blocks in petrochemical processes.
The next higher-boiling fractions, called naphtha and kerosene, are used in the production of
gasolines and jet fuels and contain components in a range centering around 7 carbon atoms. The
next higher-boiling fraction, middle distillates, is the stock from which diesel and light fuel oils
are made. The still higher boiling fractions become the heavier fuel oils and lubricating oils.
While some of these initial fractions may be satisfactory as final products (e.g., heavy fuel
oil), most require additional processing such as further separation, solvent finishing, or
reforming in the presence of a catalyst. Additional processing such as cracking, conversion, or
reconstruction may be required. In these processes, the fractions are converted to salable
products by cracking (i.e., splitting the molecules into smaller carbon compounds) then
rearranging the molecular structure. Middle distillate and fuel oil fractions are often processed
to break them up into smaller components (cracking) to increase the yield of gasolines and other
light products. The heavy residues can be used directly as residual fuel oils, or processed to
give lighter fractions.
Typically Used Processes
There are five basic processes that are common to many refineries. These include desalting
(removing salt from the crude oil), distillation and fractionation (separating different organic
fractions from the raw crude), cracking (breaking down large carbon molecules into smaller
ones), reconstruction (changing the form of the molecule), and treating (purifying various
fractions for end uses). These are shown schematically in Figure 1 and are discussed briefly
below.
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Technology Overview
Desalting
Brine is typically produced with crude oil. Salt concentrations in brine vary from almost
zero to hundreds of kilograms of sodium chloride (NaCl) per 1,000 barrels (bbl). To extract
the salts, the crude is processed through a desalter. The desalter is usually upstream of the
distillation unit so that corrosion of equipment is minimized. The removed salts become part
of the refinery waste stream.
Salts are removed as brines in settling towers, usually at elevated temperatures (90 - 145 °C;
200 - 300 °F) and pressures (3.4 -17 atmospheres; SO - 250 pounds per square inch [psi]). The
towers are packed with sand, gravel, or excelsior. Caustic is sometimes added to adjust pH.
In some cases, an electrical field (16,500 - 33,000 volts) is applied across the vessel to cause
droplets to coalesce more rapidly. Chemicals (such as modified fatty acids, partly or wholly
saponified with ammonia; oil-soluble petroleum sulfonate; water-soluble solvents; oil-soluble
solvents or inorganic sulfates) are used to improve the efficiency of the desalting process.
Distillation and Fntctionation
The crude oil is composed of a variety of carbon compounds. Typically, there are lighter
carbon chains that may be volatilized and removed from the crude stream. Distillation is a
method of separation by which a gas or vapor from the liquid crude is generated by applying
heat in a process vessel. The gases and vapors are collected and condensed into liquids.
"Topping" refers to the distillation of crude petroleum to remove the light fractions only.
Typically, the crude distillation unit in a refinery is called the "topping unit."
Fractionation is a method of separation in successive stages, each stage removing some
proportion of a component from the crude stream, as by distillation, or by differential solubility
in water-solvent mixtures. Crude oil is fractionated by distilling at the lowest boiling point,
collecting the distillate as one fraction, then collecting the next fraction as the component with
the next highest boiling point begins to distill. The fractions are then processed in other refinery
units to make specific products.
A typical topping unit will resolve the crude into the following fractions:
By distillation at atmospheric pressure:
'• A light, straight-run fraction (gasoline blending stock), primarily consisting of the Cs and
C6 hydrocarbons, but also containing some C4 and lighter hydrocarbons, which are routed
to a central gas-concentration unit for further resolution. The stabilized C5/C6 blend
usually contains odorous mercaptans, which normally are treated for odor improvement
before delivery to the refinery gasoline pool.
• A naphtha (kerosene) fraction having a nominal boiling range of 93 - 204 °C (200 - 400
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Technology Overview
• A light fuel oil distillate with boiling range of 204 - 343 °C (400 - 650 °F).
By vacuum flashing:
• Heavy fuel oil having a boiling range of 343 - 566 °C (650 - 1,050 °F)
• A nondistillable residual pitch.
Cracking
Cracking is the breaking up of large carbon chain molecules to make shorter ones. This is
done to increase the gasoline fraction of the final products.
Catalytic Cracking
Catalytic cracking is the conversion of high-boiling hydrocarbons into lower-boiling types
by reacting in the presence of a catalyst. A distilled gas-oil stream is fed at elevated
temperatures from 460 - 515 °C (860 - 955 °F) to a vessel containing a catalyst bed (usually
silica-alumina) in which the compounds are converted to simpler hydrocarbons, usually of a
higher octane number. Light olefin is usually produced as a byproduct. The catalyst
arrangement employed (fixed bed, fluid bed, multiple bed, single bed, etc.) varies, but the
catalyst is always regenerated until it is spent. The spent catalyst is a unique waste stream which
may, in some cases, be a hazardous waste.
The primary function of catalytic cracking is to convert into gasoline those fractions having
boiling ranges higher than that of gasoline. After treatment for odor control, the produced
fractions are blended with other gasoline stocks. An important secondary function is to create
light olefins such as propylene and butylenes to. be used as feedstocks for motor-fuel alkylation
and petrochemical production. Although the principal feedstock is the gas oil separated from
the crude by distillation, this feed is often supplemented with light distillates and with distillate
fractions resulting from thermal coking operations.
For practical reasons, the cracking of distillate feedstock to lighter materials is not carried
to completion. The remaining, lincracked distillates (cycle oils) are usually used as components
for domestic heating fuels (generally after hydrotreating) and are blended with residual fractions
to reduce their viscosity to make heavy fuel oil. In some refineries, however, cycle oils are
hydrocracked to complete their conversion to gasoline.
The principal products then, are gasolines, whose unleaded octane numbers range from 89
to 93, and light olefins. Another product is isobutane, a necessary reactant for the alkylation
process.
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Technology Overview
Catalytic Hydrocrocldng
In a sense, hydrocracking is complementary and supplementary to catalytic cracking because
hydrocracking occurs over a catalyst in a hydrogen environment with heavy distillates and, in
some cases, with cycle oils which,are impractical to convert completely in catalytic cracking
units. The purpose of hydrocracking is to produce additional gasoline stock from heavy
materials. The process also takes place at lower temperatures and higher pressures than fluid
catalytic cracking. Generally, the C5-C6 fraction is blended into the gasoline pool, and'
occasionally the heavier portion of the gasoline is also blended into the gasoline pool although
the primary products are gasoline or jet fuels and other light distillates. An important secondary
product is isobutane. Sometimes this portion is reformed first, to improve its octane number.
Figure 1 shows only heavy gas oil as a feedstock, and in the figure, the entire liquid product as
gasoline is routed directly to the refinery gasoline pool even though the processes described
above are performed widely in various combinations.
Thermal Crocking
The heavy fractions, as produced by most vacuum-flashing units, are too viscous to be
marketed as a heavy fuel oil without further treatment. In some refineries, the pitch processing
in a thermal cracking unit (visbreaking) at relatively low temperatures and short contact times
reduces viscosity sufficiently. Additional viscosity reduction is obtained by blending in
catalytically produced oil to produce marketable residual fuel oil.
In certain situations it is more economical to process the pitch in a thermal coking unit
resulting in gasoline, distillates, and coke. The gasoline from a coking unit is handled as
previously described. The coke can be used, after calcination, for electrode manufacture when
it meets certain purity specifications, but the coke is used principally as a metallurgical coke or
fuel. Distillates from thermal coking operations may be used as feedstock for catalytic cracking
or the lighter distillates may be routed to the refinery distillate produce pool for hydrotreatment.
A few refiners obtain additional feedstock for catalytic cracking or hydrocracking operations
by solvent extraction of the vacuum pitch, usually with propane as the solvent. The extract is
relatively free of organometallic compounds and highly condensed aromatic hydrocarbons which
are difficult to crack. Thus, the extract is suitable for handling by catalytic units. Extracted
pitch is processed subsequently in thermal units or converted to asphalts.
The small amount of thermal gasoline that is made as a byproduct is routed after treatment
to the gasoline pool or to catalytic reforming through a hydrotreating unit because its octane
number is relatively low.
Reconstruction
Reforming is the rearranging, in the presence of a catalyst, of hydrocarbon molecules in a
gasoline boiling-range feedstock to form hydrocarbons having a higher antiknock quality.
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Technology Overview
In order to raise the octane rating of the heavy naphtha fraction (Figure 1) (which varies
with the crude source, normally ranging from 40 to 50) so that it will be a suitable component
for blending into finished gasoline pools, the chemical composition of the fraction must be
changed. This is usually accomplished by catalytic reforming.
It should be noted that practically all naphtha stocks fed to catalytic reforming units are
hydrotreated to remove or inactivate arsenic, sulfur, and nitrogen compounds that would
deactivate the catalyst. The resulting naphtha, called reformate, is then fed into the gasoline'
blending pool. Byproducts of this process include hydrogen that is used in hydrotreating or
hydrocracking. Reforming of natural gas or light naphtha fractions with steam also produces
hydrogen.
Hydrotreating
As a processing tool, hydrotreating has numerous applications in a refinery,. Its principal
function is to saturate olefins and convert oxygen, sulfur, and nitrogen to compounds that can
be removed. It also converts other impurities such as arsenic to more easily removable
compounds. The process employs hydrogen and a catalyst. The use of hydrotreating for
pretreating naphthas prior to catalytic reforming has been already mentioned.
Figure 1 shows hydrotreatment of the crude light distillate (kerosine middle distillate) and
the catalytic cycle oil in a single block before being routed to the refinery light distillate pool.
Occasionally the light distillate in the crude may be sufficiently low in sulfur content to bypass
hydrotreating; usually, however, part of the stream must be hydrotreated to remove native sulfur
compounds. Some refineries hydrotreat parts of their catalytic cracking feeds, particularly if
they originate from thermal operations or if they are inordinately high in sulfur content.
Desulfurization is also an objective in the production of low sulfur residual fuel oils. Sulfur
content of reduced crudes (> 4 %) can be reduced to about 1 % by vacuum flashing,
hydrodesulfurizing the overhead vacuum-distilled gas oil and blending the gas oil of low sulfur
content with the untreated pitch to obtain a reconstituted low-sulfur fuel oil.
Alkylation
In motor fuel refineries, the alkylation units produce a high quality paraffinic gasoline by
the chemical combination of isobutane with propylene and/or butylenes. A small amount of
pentenes is also alkylated. The alkylation is accomplished with the catalytic aid of hydrofluoric
acid (HF) or sulfuric acid (H2S04) to produce a gasoline with unleaded octane numbers that range
from 93 to 95.
Propane and n-butane associated with the olefins in the feedstocks are withdrawn from
alkylation units as byproducts. Part of the n-butane is routed to the gasoline pool .to adjust the
vapor pressure of the gasoline to a level permitting prompt and easy starting of engines. The
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Technology Overview
remainder of the n-butane and the propane is available for LPG, a clean fuel that is easily
distributed as bottled gas for heating purposes.
Polymerization
Polymerization involves the combination of small molecules (i.e., ethylene) into somewhat
larger compounds (C6 and higher) including cyclic compounds such as benzene and toluene.
Polymerization is usually carried out thermally in the vapor phase at 510 - 595 °C (950 -
1,100 °F) for extended periods of time. Reaction pressures are about 170 atmospheres (2,500
psi) with a yield of 62 - 72 % by weight.
Catalytic polymerization is carried out in the presence of phosphoric acid or other catalysts
(silica-alumina, aluminum chloride, boron trifluoride and activated bauxite). Phosphoric acid
is used in three forms (quartz wetted with liquid acid, acid-impregnated pellets, or solid catalyst
pellets) packed in tubes surrounded with cooling water. This process operates at pressures of
17 - 60 atmospheres (250 - 900 psi) and temperatures of 155 - 230 °C (310 - 450 °F).
Isomerization
In this process, normal paraffins are converted to branched chain paraffins in order to
produce higher octane gasoline. Aluminum chloride is the principal catalyst used for this
purpose. Temperatures range from 80 - 130°C (180 - 270 °F) with pressures of 13 - 20
atmospheres (200 psi).
Reforming
Reforming is a process in which a variety of complex and cyclic hydrocarbons are converted
to hydrocarbons to produce better gasoline and does so with a much lower use of catalysts.
Platinum and molybdenum are used to produce the following changes:
Naphthalene dehydrogenation (removal of hydrogen)
Naphthalene dehydroisomerizatidn (removal of hydrogen and isomerization)
Paraffin dehydrocyclization (removal of hydrogen and oxygenation of paraffins)
Paraffin isomerization
Paraffin hydropacking
Olefin hydrogenation (addition of hydrogen to unsaturates)
Hydrodesulfurization (addition of hydrogen and elimination of sulfur).
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Technology Overview
Treating
Gas Concentration
The gas concentration system collects gaseous product streams from various processing units
and physically separates the components to provide, usually, a C^/C4 stream as a feedstock for
alkylation and a C2 and lighter stream that is used to supply process, heat (requirements) for the
refinery.
Hydrogen sulfide is removed from gas streams where it occurs by selective absorption in
liquid solutions (usually organic amines). The H2S released from the rich solution is converted
by further processing into elemental sulfur or H2SO4 (sulfurio acid).
Coking
i
Coking is a process in which contact times are lengthened in a thermal cracker so that
polymerization or condensation products are produced. However, only the most degraded
carbonaceous high-boiling parts of the cracking reaction are exposed. Coking takes place at
temperatures over 435 °C (820 °F). The main purpose of coking is the production of coker gas
oil which is charged to catalytic or thermal crackers. In addition, coke is heated in kilns at 590
- 650 °C (1,100 - 1,200 °F) to produce artificial graphite.
The coking process has been found to be a promising method of recycling some refinery
wastes, such as tank bottoms and other heavy, oily sludges.
Asphalt Production
Asphalt is produced by vacuum flashing of hot cracked tar as part of the cracking operation
or from the steam distillation of various stages. The quality of asphalt can be improved by air
blowing with the use of ferric chloride or phosphorous cutoxide. Heavy topped crude oil or
vacuum reduced residue is heated to within 30 °C (50 °F.) of its flash point and blown with 1
- 1.6 cu. m3min'1 per metric ton (30 - 50 cu. ft./minute of air/ton of asphalt) over a period of
1.5 to 2.4 hours.
Lube Oil Production
Reduced oxide is taken to a vacuum fractionator where gas oil is removed. The various
fractions other than the residual is sent to solvent extraction where various solvents (i.e., phenol,
furfural) are used to recover the lube oil fraction. This is then sent to a solvent dewaxing unit
where propane or methyl ethyl ketone is used to remove wax. The produce is heated with clay
to remove acidity.
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Technology Overview
Current Trends
The kinds of petroleum refineries that will be built depend on a number of factors affecting
the types of petroleum products required, the location of crude supplies and markets for final
products, and the regulatory environment. The following sections discuss current trends in each
of these areas.
Supply and Demand
\.
Trends in the supply and demand of petroleum products are a function of a several factors
including changes in national economic health and regulatory requirements, weather severity
(extreme heat or cold), and events such as hurricanes and floods. The only predictable trends,
however, are caused by changes in the state of the economy and regulatory changes. Increased
economic activity during 1992, for example, spurred growth in vehicle miles traveled. This,
combined with a slowed increase in fleet-wide fuel efficiency, resulted in greater gasoline
demand. The improving economy also spurred a growth in industrial production, causing
increased demand for distillate fuel oil. If the recovery from the economic slump of the early
1990s continues, demand for gasoline and distillate fuel oil can be expected to increase
accordingly. Both motor gasoline and distillate fuel oil are already in the highest demand of all
the major U.S. refinery products.
Historically, the most predictable supply and demand changes have been due to changes in
regulatory control. Demand for residual fuel oil has been on a steady decline for some years
now because its relatively high sulfur content results in higher, expensive-to-control sulfur
dioxide emissions. This decline is expected to continue as residual fuel oil is replaced by cleaner
fuels.
The cleaner fuels requirements of the 1990 Clean Air Act Amendments (CAAA) are already
causing significant changes in the demand for motor gasoline oxygenates and their precursors.
As of November 1, 1992, all 41 cities that exceeded the national air quality standard for carbon
monoxide in 1988 and 1989 had to use gasoline containing more oxygen (average of 2.7 % by
weight) for at least the four winter months. Requirements will tighten further on January 1,
1995, when reformulated gasoline, containing at least 2 wt % oxygen and reduced amounts of
benzene and aromatics must be supplied year round in the 9 worst non-attainment areas for
ozone. As of May 1992, nine additional states had requested inclusion in this reformulated
gasoline program, and other states were considering doing the same. In addition to the EPA
program, California will require the use of reformulated gasoline year-round for all areas
beginning in 1996.
Because of these developments, U.S. demand for oxygenates (e.g. methyl tertiary butyl
ether [MTBE] and ethanol) is expected to rise to at least 411,000 barrels per day (bpd), and
possibly much higher, depending on how many additional areas opt to be included in the EPA
program. Even though U.S. oxygenate production capacity is expected to more than double
from its April 1992 level of 236,000 bpd of MTBE equivalents, it may not be able to satisfy
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Technology Overview
domestic demand. Supply shortfall could reach almost 250,000 bpd in winter months if all 96
ozone non-attainment areas are included in EPA's program.
Demand for oxygenate precursors like butane and methanol can be expected to increase
proportionally with that of oxygenates. While domestic production of such precursors is
expected to rise, it is not expected to satisfy demand. Part of the reason for this is that some
refiners are unwilling to pay the high cost of construction and environmental permits associated
with increasing production capacity. EPA may waive reformulated gasoline requirements in'
some areas in the event of supply shortages, but that is by no means certain. It is likely that
imports of finished reformulated gasoline, and oxygenates and their precursors will have to cover
much of the shortfall. Non-North American oxygenate production capacity is expected to
increase by approximately 300 % by the mid-1990s.
Alternative-fuel vehicle requirements under the CAAA will increase demand for non-gasoline
power sources. Alcohol-based fuels and liquified petroleum gases are two of the more
prominent alternative fuels. Demand for propane is expected to rise significantly due to an
additional one million new propane-fueled vehicles estimated to be purchased by government and
commercial light truck and bus fleets.
Configuration and Production Levels
Recent trends in operable crude refinery capacity and production have been varied.
During 1992 the number of operable refineries in the United States shrank from 199 to 187,
resulting in a year end capacity of 15.5 million bpd. This 1.6 percent drop was due to the
shutting down of 13 refineries as a result of more stringent product requirements and a poor
economy. Only three new refineries came on line in 1992.
Refinery inputs and production have been increasing because decreases in refinery capacity
have been offset by the activation of idle capacity. Corresponding to demand increases,
production of both motor gasoline and distillate fuel oil has been rising. As with the demand
for these products, if the national economy continues to improve, production of finished gasoline
and distillate fuel oil should increase as well. Production of residual fuel oil, on the other hand,
is declining. This trend can be expected to continue as long as demand for this product declines.
Geographic Distribution
There are a number of trends and patterns in the location of refineries and where certain
products are produced. Refineries are typically located near coastlines, for ease of transportation
of crudes by ship. Some refineries are located inland, closer to oil fields where crude is
produced. The products are then transported by pipeline or truck to distribution.
The majority of U.S. refinery capacity lies within the Gulf Coast, Midwest and West Coast
states, accounting for 44.7 percent, 22.5 percent and 19.2 percent of national capacity
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Technology Overview
respectively. East Coast and Rocky Mountain states account for only 10.2 and 3.4 percent of
national capacity, respectively.
Gasoline oxygenates are produced mostly in the Midwest and Gulf Coast regions. Ethanol,
derived from corn, is produced almost entirely in the agriculturally rich Midwest (94 % of total
ethanol production). The Gulf Coast produces the vast majority of all other oxygenates,
including 84 percent of all MTBE and 86 percent of all methanol produced.
Raw Materials
In general, there has been a proportional increase in the use of imported crudes from
Africa, the Middle East, and North and South America. Production of domestic crude has been
decreasing due to low prices and high costs.
U.S. refiners processed slightly more than 4.9 billion barrels of crude in 1992. Slightly
over half of this was domestically produced, with about one fifth coming from Alaska. Other
major domestic sources were Texas and the Gulf Coast, and California. Most of the imported
crude came from only a few countries: Saudi Arabia was the dominant U.S. crude supplier,
accounting for roughly one fourth all imports. Venezuela and Canada together also supplied
roughly one fourth of U.S. refinery inputs, with Venezuela's contribution having increased
dramatically over the last couple years. Other key sources included Mexico, Nigeria, and
Angola.
Refiners on the East Coast used 96 percent imported oil in 1992, with Nigeria and Angola
supplying 41 percent of this, and Saudi Arabia, Venezuela, Mexico and Canada supplying most
of the rest. Midwest refiners processed roughly 60 percent domestic crudes in 1992. Virtually
all of the domestic supply came from the lower 48 states. Canada supplied roughly half of
Midwest imported refinery inputs, with most of the remaining imports coming from Saudi
Arabia, Venezuela, Mexico and Nigeria.
Slightly less than half of Gulf Coast area crude inputs were from domestic sources, and
almost all of this was from the lower 48 states. Saudi Arabia, Mexico, and Venezuela accounted
for 70 percent of Gulf area imported inputs, with Nigeria, Angola, and Great Britain also being
major sources. The Rocky Mountain region refineries used just over 80 percent domestic oil
during 1992, all of it from outside of Alaska. Canada supplied their imported crudes. West
Coast states refined over 90 percent domestic oil in 1992, with 61 percent of that coming from
Alaska. West Coast imported crude inputs came mostly from Indonesia, Ecuador, and Canada.
Pollution Prevention
In general, there is a trend toward increasing environmental regulation, including more
stringent control of effluents and emissions, and reduction of allowable contaminant limits in
effluents and emissions. As laws become more stringent, traditional end-of-pipe treatment
methods are becoming economically unattractive.
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Technology Overview
In addition, the Pollution Prevention Act of 1990 specified a hierarchical national pollution
prevention policy that de-emphasizes waste treatment and disposal. The policy states that waste
should be reduced at the source through process and product modification and material
substitution whenever feasible. Wastes should be recycled back into processes, beneficially
reused, or utilized for materials recovery as a second tier. Waste disposal should be considered
only as a last resort. Because of these factors, refineries will be looking toward more waste
minimization and pollution prevention-oriented approaches for dealing with their wastes.
There will be major changes in the design of new refineries resulting in numerous equipment
improvements and process modifications to increase efficiency and reduce the amounts of
pollution and solid waste generated. Many articles and studies have been published recently in
refinery-related literature describing cost-effective, efficient new technologies and strategies for
minimizing waste and preventing or dealing with pollution. According to a recent API document
on environmental design considerations, more sophisticated process controls are available to
optimize refinery energy consumption, and thus minimize furnace and boiler emissions for any
fuel used. There may also be a trend toward the use of more accurate pollutant detection
instruments, such as energy absorption probes. Use of these probes has already enabled some
refiners to cheaply increase oil/water separation efficiencies, thereby greatly reducing the amount
of oil escaping to individual waste streams before they ever reach the WWTP (HP 8/93).
Trends in toxics control in refinery wastewater are such that emphasis will be placed on
source control, as exotic tertiary treatment is expensive and contaminant-selective. Attention
will be paid to the resulting effluent quality and source processes in treatment system design
phases. The reduction of toxics will require further data gathering to understand toxicity sources
more clearly and identify cost-effective solutions. More efficient water use and recycling are
bound to be attractive options (Frayne, 1992—HP 8/92).
In general, refinery trends in emissions reduction will focus on those pollutants subject to ,
tighter controls, such as VOCs arid oxides of nitrogen. In an 'effort by refiners to reduce
fugitive VOC emissions, new refineries will need to employ specialized hardware (e.g., better
valves, pumps, flanges, and vents) and better operation and maintenance procedures (API,
1993). Benzene emissions from refinery wastewater can be greatly reduced by stripping the
benzene from oil desalter brine-before sending the brine to the treatment plant. The stripped
benzene can then be reused in blending gasoline. Nitrogen oxide emissions can be reduced by
installing new low-NO, burners and selective catalytic reduction of flue gases.
Trends in waste management are to reduce the volumes and toxicity of wastes, partly to
meet new regulations, but also to reduce costs of disposal of hazardous waste. BDAT-qualifying
pretreatment methods such as tank-based biological treatment will have to be used. Tank-based
and other totally enclosed treatment systems may be selected as they are often exempted from
expensive RCRA permits. As on-site treatment standards become more stringent, there may also
be a trend toward separate treatment of concentrated, individual waste streams, as this is often
more cost-effective.
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Technology Overview
Coal Gasification
Prior to World II, there were more than 1,000 plants making gas from coal in the United
States to provide street lighting. During this time, coal gasification technologies improved
greatly. However, the availability of electric power and natural gas virtually eliminated coal
gasification as a source of fuel gas for domestic lighting or heating.
There were two periods in the 1970s when shortages of liquid transportation fuels developed
because of reduced crude oil production in the Middle East. The United States, being a major
consumer and importer of liquid transportation fuels, was especially hard hit. As a consequence,
the United States Synthetic Fuels Corporation (US SFC) was founded to foster development of
liquid transportation fuels and other gaseous fuels from solid fossil fuels. The Department of
Energy (DOE) and its predecessor, the Energy Research and Development Agency (ERDA), was
also involved in this effort, initiating a very large coal gasification project in North Dakota for
the production of synthetic natural gas (SNG).
Both the SFC and DOE leaned toward coal gasification projects because their products and
processes were environmentally benign, and because U.S. reserves of coal and lignite are very
large. Although the US SFC was abolished in the 1980s, the DOE continues to promote coal
gasification. Furthermore, as the electric power industry's current facilities in the United States
become obsolete, and as environmental restrictions on new power-generating sources become
more severe, coal gasification facilities should begin to replace conventional coal-burning
facilities.
Process Overview
Coal gasification is a process in which coal is converted non catalytically to a gaseous fuel
through partial oxidation. All grades of coal — anthracite, bituminous coal, subbituminous coal,
lignite, and even peat — are amenable to coal gasification, but generally only bituminous and
subbituminous coals and lignite are used. The resulting gaseous fuel is subjected to various
purification steps to remove suspended solid paniculate matter, and acid gases (primarily
hydrogen sulfide [H2S], carbonyl sulfide [COS], and CO2). Removal of these constituents is
desirable and necessary to make- the fuel more environmentally acceptable.
When a fuel is burned, its potential chemical energy is convened to heat, and this can then
be converted to mechanical or electrical power. When oxygen available from the air combines
with the carbon (C) and hydrogen (rf or H2), the common products of combustion, along with
heat, are carbon dioxide (COj) and water vapor (H2O). Both of these products are fully oxidized
and cannot be oxidized further. However, if the available supply of oxygen is decreased, other
products, such as carbon monoxide (CO), hydrogen, and methane (CH4), are formed. All of
these products are gaseous, can be readily and inexpensively transported, and can be burned for
energy release at another place.
The chemistry of coal gasification is complex. The principal reactions are as follows:
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Technology Overview
Exothermic reactions that give off heat
Carbon combustion:
C + 03 = C02 (1)
C + 1/2 02 = CO (2)
Water-gas shift:
CO + H20 = CO2 + H2 . (3)
Methanation:
CO + 3 H2 = CH, + H2O (4)
i
C + 2 H2 = CH4 (5)
Endothermic reactions that absorb heat
Boudouard reaction:
C + CO2 = 2 CO (6)
Steam-carbon reaction:
C + H20 = CO + H2 (7)
. Hydrogen liberation:
2 H (in coal) = H2 (gas) (8)
Although some reactions release heat and others absorb heat, the net result is autothermic —
sufficient heat is released and sufficiently high temperatures generated so that both types of
reactions take place simultaneously.
There are two main reaction stages that occur in gasification: devolatization and char
gasification. The first stage, devolatization, begins to occur as soon as coal enters a hot gasifier.
The organic matrix in the coal breaks down to form hydrocarbon gases, oils and tars, and
phenols. . Depending on gasifier configuration, residence time, and reactor temperature, these
materials may pass out of the reactor or may be further reacted to CO, COj, H2O, and H2.
After volatilization, a substance called "char" remains. Char is composed primarily of ash and
carbon, and generally most of the carbon is reacted to form gaseous products. Depending on
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Technology Overview
reactor configuration, coal characteristics, and operating temperatures, the residual from
combustion of char is removed from the reactor as an ash or a molten slag. Fused ash, in a
molten state, is known as slag, which solidifies upon cooling.
Typical Configurations
Although there are numerous coal gasification processes, they are generally of three major
types based on reactor design: moving bed gasifier, fluidized bed gasifier, and entrained flow
gasifier. These are described briefly below.
Moving Bed Gasifiers
In this design (sometimes also referred to as a fixed-bed gasifier), coal is introduced at the
top of a reactor onto a grate. Steam and air (or oxygen) are introduced at the bottom of the
reactor, and pass upward through the grate and the bed of coal. As the coal is consumed by
reacting with steam and oxygen, it forms ash or slag, which falls through the grate and is
removed at the bottom of the reactor. Thus, the bed of coal appears to move slowly toward the
grate.
When coal is first introduced to the reactor at the top of the column, it loses moisture and
is heated. With continued heating, it descends and begins to volatilize. Some of the volatile
matter reacts to produce a fuel gas, but some leaves the reactor and is recovered downstream.
In the last stage, coal has descended almost to the grate and only char remains. The char reacts
with the incoming steam and oxygen to form fuel gas, and residual ash or slag falls through the
grate and is removed from the reactor. Total residence time of the coal and its solid
intermediates in the reactor is about 30-60 minutes.
Fluidized Bed Gasifiers
In this design, crushed coal panicles are introduced into a dicrate fluidized bed of coal
where the particles are in various stages of gasification. The fluidizing gas is a mixture of steam
and oxygen (or air). The reaction must be maintained below ash fusion temperatures in order
to avoid formation of clinkers (large agglomerates of molten, fused ash particles, or slag) that
would affect the behavior of the fluidized bed. Conversely, an agglomerate fluidized bed
provides a hot zone where ash particles can be agglomerated to a controlled size prior to
removal from theiluidized bed.
Entrained Flow Gasifiers
This type of gasifier features concurrent down-flow of both coal and steam-plus-oxidant.
It can handle most grades of coal and it features a high level of heat generation in a short
reaction period. Because of the high temperatures involved, the process always results in slag
formation rather than ash.
A more detailed breakdown of gasifier characteristics is presented in Table 1.
35
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Technology Overview
TABLE 1. GASIFIER CHARACTERISTICS
Moving BPH
Aril Conditions:
Dry Ash
Slagging
FBBOCOU dmctcnstics!
Size
AnfTFtflbjliiy "f f""«
Acceptability of caking coal
Prefeffcd coal tank
Coane (< 2 inches)
f - •
•HimuDo
Yes (with modifications)
Low
Coarse (< 2 inches)
Belter than dry ash
Yes (with modifications)
High
Operating chsractensocc
cut gas temperamvB
Oxidrnt requirement
Steam requirement
Key distinguishing characteristics
Key technical issue
Low(800tol200T)
Low
High
Low(800tol200°F)
Low
Low
Hydncffbon licpikJi in the raw gas
FluidJMd Rt»d
Aril Condlttoos:
Feed coal chanctcniucK
Size
Acceptability of fines
Acceptability of caking coal
rYeiored coal rank
Operating dmartfiiBirr
Exit gas banperaam
Ondantrequimnent
Stcun n^umiiicnt
Keydistinguichingchancterinics .
Key technical issue
Dry Ash
Crashed (<0.25 inches)
Good
Possibly
Low
Agglomerating
Crushed (2300°F)
High
Low
Large amount of sensible heat energy in the hot raw gas
Ras gas cooling
Reproduced with permissiuii of Babcock and Wilcox.
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Technology Overview
Msyor Products
In addition to categorizing coal gasifiers by reactor design, they can also be classified by
products created (final products are always the result of additional reaction steps subsequent to
gasification). In broad terms, coal gasifiers are operated in order to:
• Produce a low BTU fuel gas for use in generating electrical energy, steam, or a
combination of both
• Produce gaseous hydrogen for subsequent manufacture of ammonia or for use in hydro-
genation operations in petroleum refineries
• Produce gaseous chemical intermediates which can be used to produce synthetic natural
gas (SNG) or chemicals such as methanol or acetic acid.
Each of these is described below.
Fuel Gas
There are three major types of operations generating fuel gas in the United States: for
electric power generation, hydrogen generation, or synthetic natural gas production. Each of
these is described briefly below.
Electric Power
Construction of coal gasifiers in the United States is primarily directed toward production
of low BTU gases (160 - 350 BTU/standard cubic foot [sfc]) for combustion in "integrated
gasification combined cycle" (IGCC) facilities. In such facilities, coal is partially oxidized with
air or oxygen, and after cleaning, the gas is burned in a gas turbine to produce electrical power.
The hot exhaust gases from the turbine are then directed to a "heat recovery steam generator"
(HRSG) to produce high pressure steam that is then discharged through a steam turbine to
produce additional power. If steam is also needed for other purposes, it can be removed from
the HRSG. The practice of producing electrical power from both hot gases and steam, plus
diverting some steam for process use, is termed "cogeneration."
Hydrogen
The practice of gasifying coal to furnish the energy required to produce hydrogen from
water is used in many locations in the world. The primary uses for the hydrogen are as raw
material for the commercial production of ammonia and, to a lesser extent, for hydrogenation
of petroleum stocks.
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Technology Overview
Synthetic Natural Gas (SNC) and Chemicals
The production of gaseous chemical intermediates for producing organic chemicals and
liquid fuels is also practiced in many-parts of the world. Most of the liquid fuels used in South
Africa are based on conversion of gases produced from low-grade coal. In the United States,
the Tennessee-Eastman Company, in Kingsport, TN, produces methanol, acetic acid, and other
organic chemicals from gases produced by a Texaco coal gasifier. In Beulah, ND, a very large
facility based on the Lurgi coal gasification technology uses about 22,000 tons per day of lignite
to produce about 138 million sfc of pipeline-quality SNG. Other, but minor products include
phenol and ammonia. A facility of this type could also produce methanol, and in turn, gasoline
from the methanol.
Typical Processes
There are no standard or typical processes in use for coal gasification. The best appreciation
for the range of processes currently in use is gained by understanding some of the range of
technologies presently employed. A few of the more significant technologies are presented in
Table 2. A sampling of projects is described below.
•
Coal Gasification
there are several coal gasification projects in the United States that have been successfully
operated for up to 9 years. There are also five full-scale coal gasification demonstration projects
that are supported by the DOE and are either in the planning and design stage, or are in
construction. Some of these existing and planned projects are discussed in the following
paragraphs to develop the breadth of designs, technologies, products, and uses that are
encompassed by coal gasification technologies and gas cleaning processes.
Combustion Engineering IGCC Repowering Project
This project will be located at the Springfield, IL, City Water, Light and Power's
Lakeside Station, and will demonstrate Combustion Engineering's dry feed, air blown,
two-stage, entrained-flow coal gasifier with a moving-bed zinc titanate, hot gas cleanup system.
The following description of the project and process is taken from a DOE document
(DOE/FE-0272).
"Six hundred tons per day of pressurized pulverized coal is pneumatically transported to the
gasifier. The gasifier essentially consists of a bottom combustor section and a top reductor
section. Coal is fed into both sections. A slag tap at the bottom of the combustor allows
molten slag to flow into a water-filled quench tank."
"The raw, low-BTU gas 100-150 BTU/scf (HHV) and char leave the gasifier at
approximately 2,000 °F and are reduced in temperature to about 1,000 °F in a heat
exchanger. Char in the gas stream is captured by a high-efficiency cyclone, as well as by
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Technology Overview
TABLE 2. PARTIAL LIST OF GASIFICATION TECHNOLOGIES
Technology
Texaco Gasification
Power Systems
Shell Coal Gasification
Processes
Noelle Gasification
Technology
KRW Gasifier
Destec Coal Gasifier
MCTI Pulse
Combustion Process
Tampella U-Gas
Gasification System
Lurgi Coal Pressure
Gasification Process
British Gas/Lurgi Coal
Gasifier
Lurgi Circulating Fluid
Bed Gasifies
rugu iciupraaiUIC
Winkler Gasification
Process
Combustion
• Engineering Coal
Gasification Process
lyjfi
Entrained flow,
oxygen blown
Entrained flow
. Entrained flow.
oxygen blown
Pressurized fluidized
bed, air blown
Entrained flow,
oxygen blown
Fluidized bed, steam
blown
Fluidized bed, air
blown
Moving bed, oxygen
blown
Moving bed, oxygen
blown
Fluidized bed, air or
oxygen blown
Fluidized bed, air or
oxygen blown
Entrained flow, air
blown
U.S. Vendor or Owner
Texaco Development Corporation,
Texaco Inc., White Plains, NY
Synfuels Business Development, Shell
Oil Company, Houston, TX
Noelle Inc., Hemdon.VA
M.W. Kellogg Company, Houston, TX
Destec Energy, Inc., Houston, TX
Manufacturing and Technology
Conversion International. Inc.,
Columbia, MD
Institute of Gas Technology, Chicago, IL
Lurgi Corporation, Paramus, NJ
Lurgi Corporation, Paramus, NI
Lurgi Corporation, Paramus, NJ
Lurgi Corporation, Paramus, NJ
ABB Combustion Engineering Systems,
Windsor, CT
39
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"V'V
•
Technology Overview
•
*
.
v
a subsequent fine-particulate removal system, and recycled back to the gasifier."
.
"A newly developed process consisting of a moving bed of zinc titanate sorbent is being
used to remove sulfur from the hot gas. Paniculate emissions are removed from the
coal-handling system and gas stream by a combination of cyclone separators and baghouses,
and a high percentage of particulates are fed back to the gasifier for more complete reaction
and ultimate removal with the slag."
•
The cleaned low-BTU gas is routed to a combined-cycle system for electric power
production. About 40 megawatts (MW) are generated by a gas turbine. The gas turbine is used
to provide the high-pressure air requirements of the gasifier and the zinc titanate desulfurization
system. Exhaust gases from the gas turbine are used to produce steam which is fed to a
bottoming cycle to generate an additional 25 MW for a total of 65 MW.
The anticipated heat rate for the repowered unit is 8,800 BTU/kilowatt hour (an efficiency
of 38.8 %), and SO2 emissions are expected to be less than 0.1 Ib/million BTU (99 % removal).
NO. emissions are also expected to be less than 0.1 lb/million BTU (90 % removal).
Figure 2 presents the essential details of the gasifier and its process train.
WATER
SLAB TO
STEAM 1
FIGURE 2. SCHEMATIC FLOW CHART OF COMBUSTION ENGINEERING'S IGCC PROJECT
IN SPRINGFIELD, ILLINOIS
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Technology Overview
Some of the salient features of this project are:
• The oxidant for coal is air so no auxiliary oxygen plant is required. Compared to
facilities requiring an oxygen plant, capital and operating costs are lessened since internal
use of electric power to operate the oxygen is not needed. On the other hand, the product
gas has a very low BTU value compared to oxygen-blown gasifiers.
• All types of coal can be processed.
• No tars or oils are produced, and char is recycled. Carbon loss is therefore negligible.
• Additional heat economies are also achieved through the hot gas cleanup. Systems that
require crude gas cooling prior to cleanup and require .reheat prior to combustion result
in a loss in overall thermal efficiency.
Lurgi Gasification/Great Plains Coal Gasification Project
The Great Plains Gasification Association (GPGA) coal gasification plant, located in Beulah,
ND, is one of the few commercial-scale synthetic fuels facilities in the United States and was
the Nation's first commercial-scale coal gasification project to become operational.
The GPGA plant is massive, as indicated by the following statistics. The lignite raw
material handled is 22,000 tons per day (tpd), of which 14,000 tpd are input to the gasification
process (the coal fines balance is used by the adjacent Basin Electric power plant.) The plant's
design capacity is 137.S million standard cubic feet per day (scfd) of high-BTU pipeline-quality
synthetic natural gas (SNG), with a nominal production level of 125 million scfd (equivalent to
20,000 barrels of oil). The plant occupies about one-half of a 1,127-acre site, not including the
adjacent electric power station or the nearby coal mining and ash disposal areas.
SNG production at the GPGA facility involves the following process steps:
Coal preparation and handling
Gasification and lock gas recovery
Shift conversion
Gas cooling
Acid-gas and naphtha removal (Rectisol)
Methanation
Product gas drying and compression. •
The heart of the gasification plant is the gasifier building containing fourteen Lurgi Mark
4 gasifiers. Twelve gasifiers are sufficient to achieve design capacity. The additional two
gasifiers are spares allowing for continuous overhaul without reducing the plant output. Each
gasifier is about 14 feet in diameter and 40 feet tall. Lignite is fed through a lock hopper system
into a gasifier operating at a pressure of 430 psi. Steam and oxygen, mixed and introduced into
the gasifier from the bottom, are distributed upward through the coal bed by a rotating grate.
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"
Technology Overview
As lignite descends through the four zones in the gasifier (drying, carbonization, gasification and
combustion zones), it is reduced to ash while producing the raw gas.
The overall process requires the following auxiliary unit operations:
• Oxygen plant
• Methanol synthesis
• Steam generation
• Sulfur recovery (Stretford)
• Phosam NH3 recovery
• Phenosolvan phenols recovery.
A simplified flow diagram of the process is shown in Figure 3.
.
GOAL
SHIFT CONVERSION
RECTISOL unrr
METHANATION
GASIFIER
PIPELINE
GAS
FIGURE 3. SIMPLIFIED FLOW CHART OF THE PROCESS LEADING TO A PRODUCTION OF
SYNTHETIC NATURAL GAS AT THE GREAT PLAINS COAL GASIFICATION PROJECT,
BEULAH, ND
A few environmental highlights follow:
• The facility's most serious operating problem was experienced at its three Stretford sulfur
recovery units. The state permit allowed a maximum of 1,340 Ib/hr of SO2 emissions,
but the total of stack and flare emissions have totaled 5,000 - 7,000 Ib/hr. Although the
plant has now been operating for nine years, it is believed that SOj emission problems
still persist.
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Technology Overview
• The process water management system was designed to have a negative plant water
balance and zero wastewater discharge to surface waters, but in the early years of
operation, there was water discharge during the winter months to a tributary of the Knife
River. During summer months there is no discharge due to the high evaporation rates
in the several cooling ponds.
• The largest solid waste discharge is ash — about 1,100 tons per day. RCRA-mandated
EP toxicity tests performed on the ash indicated that this material is non-hazardous. An
ash disposal area was prepared in the lignite mining area. This area was lined with
compacted clay that was 5 feet thick at the base and 14 feet thick at the side walls.
Texaco Gasifier/Tampa Electric IGCC Project
This project is now under construction at Tampa Electric Company's Polk (County) Power
Station at Lakeland, FL. The project will demonstrate an integrated gasification combined-cycle
(IGCC) system using Texaco's pressurized, oxygen-blown, entrained flow gasifier technology,
incorporating both conventional, low-temperature acid-gas removal and hot-gas moving-bed
desulfurization. The Texaco-based system has already been proven capable of handling both
subbituminous and bituminous coals. This demonstration project scales up the technology from
Cool Water's 100 MW to 260-MW.
Texaco's pressurized, oxygen-blown, entrained-flow gasifier is used to produce a
medium-BTU fuel gas. Coal/water slurry and oxygen are combined at high temperature and
pressure to produce a high-temperature syngas. Molten coal-ash flows out of the bottom of the
vessel and into a water-filled quench tank where it is turned into a solid slag. The syngas from
the gasifier moves to a high-temperature heat-recovery unit which partially cools the gases.
The cooled gases flow to a paniculate-removal section before entering gas-cleanup trains.
About SO % of the syngas is passed through a moving bed of zinc-titanate absorbent to remove
sulfur. The remaining syngas is further cooled through a series of heat exchangers before
entering a conventional gas-cleanup train where sulfur is removed by an acid-gas removal
system. These cleanup systems combined are expected to maintain sulfur levels below 0.21
Ib/million BTU (96 % capture). The cleaned gases are then routed to a combined-cycle system
for power generation. A gas turbine generates about 192 MW. Thermally generated NO, is
controlled to below 0.27 Ib/million BTU by injecting nitrogen as a cooling diluent in the
turbine's combustion section. A heat-recovery steam-generator uses heat from the gas-turbine
exhaust to produce high-pressure steam. This steam, along with the steam generated in the
gasification process, is routed to the steam turbine to generate an additional 130 MW. The
IGCC heat rate for this demonstration is expected to be below 8,500 BTU/kWh (more than 40
% efficient, making it attractive for baseload applications). Figure 4 is a schematic flow
diagram of the project. Byproducts from the process — sulfur, sulfuric acid, and slag — can
be sold commercially, the sulfur and sulfuric acid byproducts as a raw material to make
agricultural fertilizer, and the nonleachable slag for use in roofing shingles, asphalt roads, and
as a structural fill in construction projects.
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.
1
Technology Overview
OXYGEN
PLANT
TOCOMBUSTOfl
FIGURE 4. TAMPA ELECTRIC INTEGRATED GASIFICATION COMBINED-CYCLE PROJECT,
BASED ON TEXACO ENTRAINED-FLOW GASIFIER
Commercial IGCCs should achieve better than 98 % SO2 capture with NO, emissions
reduced by 90 %.
The Texaco gasification process is versatile as it can be used to gasify a number of
feedstocks, including coal, petroleum coke, "Orimulsion" (a tar/water emulsion based on
Venezuelan tars), heavy oils, and other hydrocarbons, and even industrial and domestic wastes
such as trash and paper. In addition to the Florida project, the Texaco gasification process is
being operated or being built at two locations in Delaware, ten locations in China, and three
locations in Italy.
U-Gas Gasifier/Toms Creek IGCC Project
The project is to be built near Coebum, Wise County, Virginia, at Virginia Iron, Coal, and
Coke Company's Toms Creek Mine. The 190 MW project is based on the Institute of Gas
Technology's "U-Gas" gasifier.
44
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Technology Overview
The objective of the project is to demonstrate air-blown, fluidized-bed gasification,
combined-cycle technology, incorporating hot gas cleanup, for generating electricity and to
assess the system's environmental and economic performance for meeting future energy needs.
It will also demonstrate the newly developed zinc titanate fluidized-bed hot-gas cleanup
technology.
Coal is gasified in a pressurized, air-blown, fluidized-bed gasifier in the presence of a
calcium-based sorbent. About 90 % sulfur removal is accomplished in the gasifier. Solids
entrained in the gas are collected by cyclones in two stages. The low-BTU gas, which leaves
the secondary cyclone at 1,800 - 1,900 °F, is cooled to about 1,000 °F before entering the
post-gasifier desulfurization unit where zinc titanate is used to remove the bulk of the remaining
sulfur in the gas. This is accomplished in two fluidized beds. In the first bed, the sulfur is
absorbed by the zinc titanate; the zinc titanate is regenerated in the second bed. In the final
hot-gas-cleaning step, a ceramic candle filter removes particulates. The gas is then sent to the
gas turbine combustor which has been modified to burn low-BTU gas.
Hot exhaust gases from the gas turbine are directed to a heat recovery steam generator. The
steam generated is used both for driving a conventional steam turbine generator to produce
additional electricity and to provide steam feed to the gasifier. Figure 5 is a schematic flow
diagram of the project.
About 430 tpd of bituminous coal are converted into 55 MW by the gas turbine. A
conventional pulverized coal boiler produces another 135 MW through the shared steam turbine
generator. Also, 50,000 Ib/hr of steam are generated for export to a coal preparation plant
located next to the demonstration facility. The electric power is sold to a utility.
The U-Gas technology is capable of gasifying all types of coals, including high-sulfur and
high-swelling coal feedstocks.
The total system being demonstrated is compact, reducing space requirements, and is
amenable to small capacity, modular construction. There are no significant wastewater streams,
and the solid waste from the gasifier, ash and calcium sulfate, is disposed of as a non-hazardous
waste.
The heat rate of the demonstration facility is expected to be 8,720 BTU/kWh (39 %
efficiency) with SQ emissions reductions of 99 % (0.056 Ib/million BTU release). NO,
emissions are expected to be 0.09 Ib/million BTU.
Corollary Processes
Sh{ft Conversion
The water gas shift reaction is of immense importance. In this reaction, carbon monoxide
(CO) reacts with water (as steam) over a catalyst to produce hydrogen and carbon dioxide. The
45
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'
Technology Overview
isi
HLTgftfi
NOT PAHT OF THE 006 COST-SHARED PROJECT SCOPE
STACK
FIGURE 5. TOMS CREEK IGGC DEMONSTRATION PROJECT BASED ON INSTITUTE OF GAS
TECHNOLOGY U-GAS COAL GASIFIER
reaction, which is reversible, is used to prepare hydrogen or a synthetic gas with a higher H2/CO
ratio than the feed gas. The reaction is exothermic, is unaffected by pressure, and favors H2
production as reaction temperatures are decreased (315 - 510 °C; 600- 950 °F). Product gases
having CO concentrations of 0.2 - 0.5 % are possible. However, if the desired product is an
oxygen-containing chemical such as methanol, then a ratio of H2/CO2 close to the theoretical of
2/1 is desired, since
.
CO + 2H2 -» CH3 OH (methanol)
The water gas shift reaction is therefore used after coal gasification when products such as
hydrogen, methane (SNG), methanol, and other organic chemicals are the desired final product.
Methanation
The catalytic hydrogenation of carbon monoxide to methane occurs at elevated pressures.
Favorable temperatures for the reaction are in the range of 230 - 450 °C (445 - 840 °F). Many
suitable catalysts have been discovered, but nickel-based catalysts are used almost exclusively
46
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Technology Overview
for industrial applications. The reaction is highly exothermic, therefore heat removal must be
efficient to minimize loss of catalyst activity or plugging of the reactor due to nickel carbide
formation. This reaction is used, in conjunction with the water gas shift reaction, when pure
methane (SNG) or a methane-rich gas is desired.
Compression and Drying
Considerable volumes of water are co-produced during the methanation reaction, therefore
the product gas is cooled to condense some of the water. In subsequent multistage compression
steps, followed by cooling between each compression step, additional water is condensed and
drained off.
Current Trends
Supply and Demand
By the mid-1990s, more than half of all existing coal-fired boilers in the United States will
be 30 years old or older, and the percentage of aging plants will rise even more sharply around
the year 2000. At the same time, demand for electricity is continuing to increase. As much as
100,000 to 150,000 megawatts of additional new capacity beyond what is currently planned —
the equivalent of 200 to 300 moderately sized (500-megawatt) power plants — could be required
by the end of the century.
These two trends — aging power plants and growing electricity demand — pose serious
problems for utilities wishing to use coal unless new technology is available. Today's baseload
coal-fired power plant takes 10 to 12 years to design, permit, and build. It is probably too late
to count on major new baseload construction to meet much of the new power demand by the
year 2000.
Many clean coal technologies, however, can replace older power plants, not only reducing
emissions but extending lifetimes by 20 to 30 years. Because of the higher efficiencies, the new
technologies can boost an older plant's electrical output by 40 to 200 %. For some installations,
the effect could be the equivalent of two or more power plants at the original plant site, with
sulfur emissions reduced as much as 99 % and NO, emissions lower by 40 % than the older
plant. Coal gasification may also become the technology of choice for future, new plant
construction.
Repowering technologies, in general, replace a major portion of an existing plant (such as
the boiler) with new power generating equipment while retaining other portions of the plant
(such as the steam generating equipment). Pollution control considerations are inherent in
repowering, but more effective pollution control is not the only advantage. A repowered plant
can produce more power — sometimes twice as much or more — than the original plant, and
extend the plant's lifetime by 20 to 30 years.
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Technology Overview
Repowering comes into play when existing coal-fired plants reach the end of their useful
lives — typically 25 to 40 years after they were built — and a utility must decide whether to
retire or rebuild the facility. Repowering also becomes attractive when power generation needs
have increased and a utility wants to avoid the problems of finding and obtaining approval for
a new site. Many repowering concepts also rely on standardized, shop fabricated components.
This minimizes the costly, customized, on-site construction required for conventional
technologies.
Integrated coal gasification combined cycle technology is not the only repowering technology
available, but it is certainly a prime candidate considering its environmental advantages. Other
repowering technologies include atmospheric and pressurized fluidized bed combustors.
Improvements in Gasification Technology
The next generation of gasification combined cycle power plants will likely employ the hot
gas cleanup techniques currently being developed. These techniques remove sulfur and other
impurities in the fuel gas stream at much higher temperatures than today's technology,
eliminating or minimizing the efficiency-robbing cooling step.
One such technology sends the hot coal gas through a bed of zinc ferrite particles. Zinc
ferrite can absorb sulfur contaminants at temperatures in excess of 1,000 °F, and the compound
can be regenerated and reused with little loss in effectiveness. During the regeneration stage,
salable sulfur is produced. The technique is capable of removing more than 99.9 % of the sulfur
in coal.
Other potential technical advances are currently in research and development, and as they
are proven, they will be incorporated in industrial-scale facilities.
Fuel Cells Based on Hydrogen and Oxygen (Air)
Unlike other coal systems, fuel cells do not rely on combustion. Instead, an electrochemical
reaction generates electricity. Electrochemical reactions release the chemical energy that bonds
atoms together — in this case the atoms of hydrogen and oxygen. The concept is much like a
battery, except fuel cells produce electricity (and usable heat) as long as hydrogen and oxygen
are fed to them.
The fuel cell is extremely clean and highly efficient. In a clean coal technology
configuration, the fuel cell is fueled by hydrogen extracted from coal gas made by a coal
gasifier. Techniques exist to clean and purify the coal gases and the principal waste products
from the fuel cell water. Fuel cells are often categorized by the substance used to separate the
electrodes, termed the "electrolyte." The most mature fuel cell concept is the phosphoric acid
fuel cell. These cells have been used in hospitals, apartment buildings, and shopping centers
and are now being developed, for utility use. Other concepts are being developed. One is the
molten carbonate fuel cell which uses a hot mixture of lithium in potassium carbonate as the
48
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Technology Overview
electrolyte. The newest type is the solid oxide fuel cell which uses a hard ceramic material
instead of a liquid electrolyte.
Scale of Operations
During the last several decades, a number of 800 -1300 MW base-loaded power plants were
built. Economics of scale and the highest possible thermal efficiency were among the factors
leading to the construction of such large units. Future projects for such power plants are more
apt to be built and operated in modular fashion in increments of 100 - 300 MWs. This offers
not only increased reliability (several modules can be operated more reliably than a single large
plant) but also shorter construction times (construction periods of 3 to 4 years, rather than 5 to
8 years for the large units). Utilities would also be able to match demand patterns more quickly
and precisely.
Geographic Distribution of Coal and Coal Gasification Projects
From the viewpoint of producing electrical power from coal in the United States, it is
expected that the greatest concentration of future coal gasification projects will be located at or
near coal-producing sites. This is an economic necessity since the cost of transporting coal by
rail or truck over long distances is much more expensive than the cost of transmitting electrical
energy. Coal deposits occur in 38 of the SO United States (see Figure 6), however these deposits
are missing or meager in eastern states including New York, New Jersey, and all the New
England states, plus Florida, Georgia, South Carolina, Minnesota, Wisconsin, California, and
Nevada. Where the cost of importing coal is excessive, public utilities have several alternatives
for power generation: import electrical power, or produce power from imported or locally
produced natural gas and petroleum products.
In very general terms, the predominant coal in the midwest and eastern deposit is bituminous
coal with a relatively high sulfur content. Western coals are mostly subbituminious coal and
lignite, with lower sulfur content. The choice of coal gasification technology selected for a
given site depends somewhat on the type of coal available, but most of the recently developed
coal gasifiers are flexible with respect to their coal handling requirements.
In-situ or Underground Coal Gasification
In underground gasification, steam and oxygen are injected into a coal seam through wells
drilled from the surface. The coal seam is ignited and partially burned. Heat generated by the
combustion gasifies additional coal to produce fuel-grade gases. The gases are piped to the
surface where they are cleaned and processed using the same techniques applied in surface
gasification.
Underground gasification may be particularly useful in extracting energy from coal seams
that are unmineable. Seams that slope steeply from the surface or are too deep or of marginal
quality may be future candidates for in-situ gasification.
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Technology Overview
FIGURE 6. OCCURRENCE OF COAL IN THE UNITED STATES
Since the earth serves as the gasification reactor and repository for residual ash, and since
the coal mining and transportation steps are not needed, the economics of in-situ gasification are
very attractive. However, depending on site geology and hydrogeology, environmental risks
associated with possible aquifer contamination and eventual land subsidence may be
considerable. We do not believe that this technology is under development in the United States
at this time, but, allegedly, the Russians are experimenting with these technologies.
Combatting the Greenhouse Effect
The earth's temperature is largely regulated by atmospheric gases. Carbon dioxide (COO,
methane, and other gases such as nitrous oxides and chlorofluorocarbons (CFCs) allow the sun's
energy to penetrate to the earth, but trap the heat radiated from the earth's surface. This
phenomenon has been termed the "greenhouse effect."
There is some uncertainty in the estimates of the global budget of these greenhouse gases.
Although the sources of most of these gases have been well characterized, the sinks for them
have not been defined with certitude. However, it has been estimated that U.S. coal combustion
contributes as much as 8% of the total worldwide release of CQ attributable to anthropogenic
activities.
50
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Technology Overview
Some technological improvements can offer alternatives to regulations for mitigating the CO2
release from coal combustion. For instance, many coal technologies are effective in reducing
COj because they increase power generating efficiencies. In higher efficiency systems, less CO2
is produced per unit of fuel consumed. For example, technologies like pressurized fluid bed and
gasification combined cycle boost energy utilization efficiencies into the 40% to 45% range.
This can reduce CO2 emissions by 17% to 27% over conventional coal technologies. Future
technologies such as gasifier/fuel cell combinations could lower CO2 emissions by up to 40%.
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Technology Overview
52
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Environmental Documentation
4. ENVIRONMENTAL DOCUMENTATION
EPA's NEPA regulations (40 CFR Part 6) specifically assigns EPA the responsibility for
determining whether their proposed action (issuing a NPDES permit) will cause significant
environmental impacts. EPA is also responsible for the scope and content of the environmental
assessment and draft and final EISs. The regulations, however, indicate that "Information
necessary for a proper environmental review shall be provided by the permit applicant in an
environmental information document." EPA staff is directed to consult with the applicant on
the scope of the information that the applicant provides.
In preparing these guidelines, it was assumed that EPA staff would typically ask the
applicant for information in a format that is easily incorporated into a Draft EIS and would be
most familiar to agency NEPA reviewers. The standard order for a Draft EIS is identified in
EPA NEPA regulations 40 CFR Part 6.201:
(a) Cover sheet
(b) Executive Summary
(c) Table of contents
(d) Purpose of and need for action
(e) Alternatives including the proposed action;
(0 Affected environment
(g) Environmental consequences of the alternatives
(h) Coordination (including list of agencies, organizations, and persons to who copies of
the EIS are sent)
(i) List of preparers
(j) Index (commensurate with complexity of EIS)
(k) Appendices.
The remainder of this document follows the order, of the body of the EIS: purpose and
need, alternatives, affected environment, environmental consequences, and summary topics.
Unlike an EIS, it does not present a specific project and its environmental effects, but discusses
the kinds of data, analyses, methodologies, and qualitative and quantitative approaches EPA staff
are likely to consider in a data request to a new source NPDES permit applicant.
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Environmental Documentation
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Purpose and Need
5. PURPOSE AND NEED
The "Purpose and Need" section of an EIS requires the clear specification of the underlying
purpose and need to which EPA is responding. In the case of new source facilities, the purpose
and need section must specify the goals and objectives of the applicant. The purpose and need
must be a clear, objective statement of rationale for the project.
The importance of the statement of purpose and need is that it identifies and describes the
alternatives evaluated and the selection of the chosen action. The alternatives that must be
considered are those that fulfil the purpose and need, not just alternatives to a proposed project.
If the purpose is to build a new petroleum refinery, the alternatives could consider other
locations or a different delivery schedule. If, on the other hand, the purpose is to provide
transportation fuels to meet fuel demands, the alternatives could include conserving fuels through
fuel-efficient vehicles, different kinds of fuels (gasohol, LPG), different locations, or a
combination of some of the above. The more extensive the range of possible alternatives, the
greater the possibility of avoiding significant impacts.
The applicant for a new source petroleum refinery or coal gasification facility would most
likely be responding to a perceived future demand for fuels and should consider all the options
available to them. Since the only alternatives that need be considered are those that can fulfill
the stated purpose and need for the project, the choice of the purpose and need statement is
critical to a full examination of possible alternatives and the selection of the chosen action.
The information requested of the applicant needs to elicit a clear demonstration of why the
project is needed. Typically, historical and projected data from a number of different sources
(e.g., local or regional governments, state energy management or regulatory agencies,
institutions, community groups) are used to present a clear need. The applicant should
demonstrate, in this section, that a full range of options were considered before a new facility
was proposed.
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Purpose and Need
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Project Alternatives
6. PROJECT ALTERNATIVES
The "Alternatives" section of the EIS contains descriptions of all alternative actions or
projects that were, or are, being considered. Reasonable alternatives are explained in detail.
Alternatives that were considered and rejected early in the planning process are briefly described
with the rationale for their dismissal. Dismissed alternative are usually those that are
unreasonable for technical, economic, or institutional reasons. The rationale must have sufficient
data to support the decision not to proceed with dismissed, alternatives and sufficient backup data
to respond to a challenging question or comment on the Draft EIS.
New source NPDES permit EISs have several different general categories of alternatives:
alternatives available to EPA, alternatives considered by the applicant, and alternatives available
to other permit agencies.
Alternatives Available to EPA
EPA has three basic alternative actions that can be taken on new source NPDES permit
applications:
(1) Take the action (i.e., grant the permit)
(2) Take the action on a modified or alternative project, including one not considered by
the applicant
(3) Deny the action (i.e., reject the permit application).
The third option is usually called the "no action alternative."
Alternatives Considered by the Applicant
The applicant should provide to EPA, as part of the NPDES permit application, EID, or
other data, a detailed description of each reasonable alternative they considered and a brief
description of the alternatives they considered and rejected. A "no project alternative" should
also be described.
The "no project alternative" of the applicant and the "no action" alternative of EPA are not
the same even though the outcome may be the same. EPA's action relates to making a decision
on whether or not to grant a NPDES permit, while the applicant's "no project alternative" relates
to not achieving their goal (e.g., not meeting consumer demand for fuels). The applicant may
be able to achieve their goal through some other means (alternative) that does not require a
NPDES permit (e.g., alternative fuels).
EPA NEPA regulations (40 CFR Part 6.203 [b] [1]) require: (1) "balanced" descriptions
of each alternative considered by an applicant and (2) discussion covering "size and location of
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Project Alternatives
facilities, land requirements, operations and management requirements, auxiliary structures such
as pipelines or transmission lines, and construction schedules."
When large fuel needs are projected, companies typically undertake screening processes and
feasibility studies to help them identify and refine reasonable alternatives. The companies
investigate fuel types, siting, process types, and other topics. These screening processes provide
the bases for determining various alternatives that can be identified and investigated further.
The siting process typically includes analyses of constraints and opportunities for conflicts
such as the presence of critical habitat for an endangered species, an important historical site,
or an active earthquake fault as well as other physical, hydrologic, biological, land use, access,
economic, and air quality parameters. Siting studies may-be used for new source facility
locations, pipelines, transmission lines, or other facilities; each with different criteria and
rankings.
As part of the description of alternatives, the applicant's screening processes and results
should be explained to provide insight into the breadth and depth of alternatives considered and
rejected or pursued for further study. Explaining how the applicant narrowed the list of
alternatives can significantly reduce questions on whether conservation and demand side
management were considered, non-traditional fuel sources were given fair consideration,
particular locations for pipelines or transmission lines were chosen, and many others. A
well-documented explanation of the screening processes of the applicant is critical to complying
with the requirement for a thorough consideration of alternatives. A description of the screening
process is also often required by state or local agencies.
Alternatives Available to Other Permitting Agencies
The third category of alternatives are those available when EPA is preparing a joint EIS or
other environmental document with another federal or state agency. These additional alternatives
relate to the other federal, state, or local entity's discretionary decisions or permits and typically
include: grant the permit; grant the permit with modifications; or deny the permit.
Proposed Projects
The applicant may have a proposed project or may wait until the final EIS is being prepared
to identify a preferred alternative from among several alternatives that are fully described. The
message is clear in both the CEQ and EPA NEPA regulations that a broad array of alternatives
need to be considered, and at least several reasonable alternatives need to be explored in detail
and compared. The detail on the reasonable alternatives necessary from the applicant must be
sufficient so that the potential impacts of the alternatives can be identified and compared. As
with all the of the information needed for the EIS, the applicant's environmental documentation
or EID must provide sufficient detail so that the environmental consequences can be evaluated
and compared.
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Project Alternatives
A "rule of thumb" is to provide the nature and the magnitude of "inputs" and "outputs" of
each facility in the description of each alternative. Inputs and outputs include the physical/
chemical materials involved in construction of facility operation as well as biological, social, and
institutional (e.g., employment, land use, access) information and costs.
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Project Alternatives
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Affected Environment
7. AFFECTED ENVIRONMENT
Identifying and Characterizing the Affected Environment
This section discusses the methods and means of identifying and characterizing potential
effects on the physical-chemical, biological, and socioeconomic environments; land use; visual
resources; and cultural resources. It identifies only those environmental elements that are
significant in determining impacts. The affected environment section of an EID should to be no
longer than needed to present information required to understand environmental impacts.
Background information on topics not directly related to expected effects should be summarized,
consolidated, or referenced to focus attention on important issues.
Many of the following sections indicate that the affected environment is more than what
currently exists—it is also a projection into the future. The essence of impact assessment is to
determine what will happen with (because of) the project compared to what would have
happened if the project had not been built. The most appropriate time for impact assessment is
that point in facility construction or operation that creates the greatest change over the current
environment. For new source facilities, this is usually at some time during construction.
Physical-Chemical Environment
The physical-chemical environment comprises the air, water, and geological characteristics
of sites where the environmental impacts of alternatives will be evaluated. This section should
provide sufficient information to determine whether impacts on these resources will be likely,
but should not dwell on information that is of only esoteric interest. Typical information needs
for this section are specified below.
Air Resources
Air resources are described by the physical dynamic behavior of the lower atmosphere and
by variations in the concentrations of various gases and suspended matter. Physical dynamic
behavior is described by parameters such as the seasonal distribution of wind velocity and the
frequency and height of inversions. Wind velocity and the frequency of occurrence of inversions
are often determined by specific local topographic features, particularly surrounding hills or
mountains. Air quality is described by the variations in the concentrations of pollutant gases in
the lower atmosphere. Both are needed to determine the environmental impacts of facility stack
emissions, the effects of mobile sources on local air quality, and the likelihood that dust will be
of importance during construction.
The description of meteorological regime(s) should include a generalized discussion of
regional and site-specific climate including:
• Diurnal and seasonal ground-level temperature
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Affected Environment
• Wind characteristics at different heights and times (wind roses are particularly helpful and
provide wind speed, direction, frequency, and stability characteristics of the atmosphere)
• Total monthly, seasonal, and annual rainfall and frequency of storms and their intensity
• Height, frequency, and persistence of inversions and atmospheric mixing characteristics
• Description of pattem(s) evident for days of significant pollution episodes; evaporation.
Under certain circumstances (where cooling ponds are integral to facility design, for
example), humidity, dew point, and evaporation rates also provide useful data for determining
water balances.
Existing ambient air quality is required to predict the resulting air quality during construction
and operation of a facility. Using existing air quality as the background, incremental increases
in air pollution concentrations can be predicted for comparison with various federal, state, and
local standards. Depending on the scale of the analysis, data should be presented for the
relevant airshed, for the site itself, or both.
Emission inventories and ambient air quality as reported by state and local air pollution
control districts are the data sources for an air basin or regional airshed level analysis. At a
minimum, major stationary sources and their emissions should be characterized, with diurnal
variations in emissions by month, year, and peak season for pollutants of concern. Projections
of increases in emissions and long-term pollutant concentrations are also important at this level.
The comparison of future trends with existing federal, state, and local standards becomes a
major design parameter for gaseous emission controls.
Site-level analyses are more detailed in their geographic scope, but require similar
information. One of the major concerns at the site level is the transport of odors, dust, and
emissions towards potentially sensitive environments. Thus local variations in' wind velocities,
frequency of inversions, and ambient pollutant concentrations may become important in
determining local impacts. Air quality models are often used to determine the directions and
ground level concentrations of pollutants of concern, and these models require most of the
information described in the previous paragraph along with specific stack characteristics such
as stack height, emission temperature, emission velocity, and the chemical composition of the
stack gases.
Water Resources
Information on water resources to be included in the affected environment chapter should
cover a description of local streams, lakes, rivers, and estuaries, as well as descriptions of
groundwater aquifers. Descriptions of water body types, flows and dilutions, pollutant
concentrations, and habitat types near potential discharges are necessary to determine the
changes in the water environment that will occur with facility construction and operation.
Descriptions of groundwater aquifers are necessary to determine the potential for contamination
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of groundwaters from site activities. Of key importance here is the depth to the water table, and
the nature of overlying soils and geologic features.
i
Descriptions of surface waters should include seasonal and historical maximum, minimum,
and mean flows for rivers and streams, and water levels or stages and seasonal patterns of
thermal stratification for lakes and impoundments. The use of surface waters (diversions,
returns, and reclamation) may also be important. Information on ambient concentrations of
pollutants is also necessary to determine resulting concentrations of pollutants with new
discharges.
Descriptions of groundwaters should include the location of recharge areas, and, in areas
of water shortage, their present uses. Chemical composition of groundwaters are not usually
important unless they are to be used as process water or are suspected to be contaminated.
If imported water is to be used at the site for process water or other purposes, the source,
quantity, and quality of the water should be described.
If the site might be subject to flooding (is within the 100-year floodplain), the dates, levels,
and peak discharges of previous floods should be reported along with the meteorological
conditions that created them. Projections of future flood levels should also be included for
typical planning levels of 50- and 100-year floods. These projections should include anticipated
flood control projects such as levees and dams that will be built in the next few years.
Soils/Geology
The physical structure of soils and their underlying geologic elements determine the extent
to which soils will be affected by facility construction and operation. Useful parameters include
permeability, erodability, water table depth, and depths to impervious layers. The engineering
properties and a detailed description of surface and subsurface soil materials and their
distribution over a site provide most of the information necessary.
Nevertheless, local and regional topographic features such as ridges, hills, mountains, and
valleys provide information on watershed boundaries, and site topography (slope and elevation
characteristics) provides information that is needed in determining the potential for erosion.
Geological features are important when there may be significant mineral resources present
or when paleontological sites and other areas of scientific or educational value may be disturbed
or overlain by facility structures.
Information on seismic events is usually not required in an EID since sites that are near
faults or seismically active areas are generally screened from consideration during siting studies.
Nevertheless, if there might be concern about earthquake damage to a facility, the history of
earthquakes in the area provides useful information to evaluate risks. Relevant parameters
include locations of epicenters, magnitudes, and frequency of occurrence.
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Biological Environment
The distribution of dominant species and identification and description of rare, threatened,
or endangered species of vegetation, wildlife, and ecological interrelationships are the three
important biological environment elements needed to identify and characterize the affected
environment.
Vegetation
In order to understand the significance of vegetation changes associated with construction
and operation of a facility, it is necessary to know the types of plant communities in the general
area and the specific distribution of vegetation types on the she itself. The presence in the area
of rare, threatened, or endangered species and unique plant assemblages are particularly
important, especially if any are likely to occur at the site. There are a variety of ways to
describe vegetation, but the most useful is to.divide the site flora into four or five "typical"
assemblages and map their distribution along with recognized scientific and educational areas.
For threatened, endangered, or rare species, however, it is necessary to map their occurrence
separate from the assemblages.
In arid areas, fire hazard should be described by describing the history of fires in the area,
projecting the severity of fire hazard in the future, and describing existing fire control and
management actions.
Aquatic and marine vegetation should be described as for terrestrial vegetation if
sedimentation and aquatic discharges are likely to be large in relation to the size of the receiving
waters.
Wildlife
The presence of wildlife at a site is largely dependent on the nature and distribution of
terrestrial vegetation. Particular emphasis should be placed on the presence of rare, threatened,
or endangered species in the general vicinity of the site, and site-specific discussions are
mandatory when the site provides habitat that is used by rare, threatened, or endangered species.
Under these circumstances, the relative abundance of all rare, threatened or endangered species
and the dominant wildlife fauna should be surveyed on site and presented in the BID.
Otherwise, a general description of the wildlife species that inhabit the area is sufficient if there
is some discussion of the importance.of the site in relation to their area-wide distribution.
Ecological Interrelationships
Ecological interrelationships between vegetation and wildlife are important in the existence
of both components. These interrelationships should be characterized before establishing
. environmental impacts to either flora or fauna, and they differ slightly between terrestrial and
aquatic environments.
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It is probably not possible to determine the extent to which plants and animals are mutually
dependent at a given site, but specific attention should be given to the food sources of dominant
or rare animal species, the factors that limit these food sources (including factors such as soil
structure and moisture content, soil surface temperature ranges, and specific soil micronutrients),
and the ability of animal species to substitute food sources should current food sources be
reduced in abundance. Ecological interdependences in aquatic systems are also important, and
aquatic communities change dramatically with large increases in nutrient or sediment discharges.
While prediction of changes in plant and animal populations is difficult under the best of
circumstances, significant changes (either positive or negative) cause concomitant changes in
both terrestrial and aquatic fauna.
Socioeconomic Environment
The socioeconomic environment encompasses the interrelated areas of community services,
transportation, employment, health and safety, and economic activity. The activities associated
with the construction and operation of new source facilities must impact human resources
(employment, population, and housing), institutional resources (services or facilities), and
economic activity. The information required to assess impacts are described below.
Community Services
Community services such as water supply, sewerage, and storm drainage, power supply, and
education, medical, and fire and police services are almost always affected by major new
projects. It is important in an BID to describe the nature of existing public facilities and services
within the general vicinity, the quality of the service provided, and the ability of the existing
public facilities and services to accommodate additional users. The most critical consideration
is the level of services that would be provided in the anticipated peak year of construction
assuming the project were to be built.
Permanent and temporary household relocations create demands on the housing market. The
number of nearby housing units, their cost, vacancy rates, and owner-occupancy rate are all
significant factors in determining the suitability of the existing housing stock for occupancy by
a temporary or permanent workforce. In addition, the present rate of growth within the housing
sector can be compared with the anticipated growth in housing supply and demand and the
amount of land available for new housing to determine whether existing policies and attitudes
toward growth are adequate to accommodate the additional residents.
Transportation
Transportation systems provide access to a facility for the import of raw materials, export
of final products, and the movement of staff and service personnel. All relevant forms of
transport for the facility should be described. For all facilities, road-based transport is of
potential significance, but railways, airways, pipelines, and navigable waterways may also be
important for some facilities. Secondary impacts to air quality resulting from transportation
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Affected Environment
requirements should be evaluated in accordance with the Clean Air Act. Current traffic
volumes, current traffic capacity, and an assessment of the adequacy of the systems for meeting
peak demands during construction or operation should be presented.
Population
Total population, rate of growth, general socioeconpmic composition, transient population,
and the urban or rural nature of the local population are parameters needed to assess the
importance of the impacts of project-induced changes on the local community. Information on
average household size, average age, age/sex distributions, ethnic composition, average
household income, percent of households below poverty level, and median educational level
allow a more refined analysis of project-induced changes. Projections of demographic trends
for the region and project area without the project are also necessary to determine the relative
impacts of the project in future years.
Employment
Employment is generated by the construction and operation of any new facility.
Construction is normally carried out by a temporary workforce of construction workers, not by
the permanent workforce in the area near the site. On the other hand, facility operation usually
relies on a permanent workforce, and the source of personnel for this workforce may be local
or from other parts of the country. In any case, increases in the number of personnel required
to build or operate a facility, direct employment, is accompanied by increases in employment
in enterprises required to support the facility, indirect (secondary, non-basic) employment, as
demands for goods and services are increased. The direct and indirect employment generated
by a project, in turn, generates movements of households, resulting in population shifts and
changes in the demographic characteristics of communities.
To determine impacts of additional employment on the local environment, it is necessary to
present information about the local labor base—where people work, what they do, their skills
and education level, their rates of pay, and the unemployment rate. The characteristics of the
unemployed population are especially important if there is an expectation that a new facility will
generate employment for them.. Projections should also be included,on anticipated trends in
employment and unemployment without the project so that project-induced changes in these
parameters can be compared against a baseline.
Health and Safety
Description of the present health and safety environment should include statistics on
industrial accidents in the local area; a discussion of air, water, and radioactive emissions from
existing facilities and their effects on the health of the local population; and an analysis of
present levels of noise and their impacts on people. The identification of applicable regulatory
standards provides a benchmark against which the present and future health and safety
environment, with and without the project, can be judged.
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Economic Activity
Economic activity will always be affected by .new facilities. Current economic activity
should be described by characteristics of local businesses (number and types of businesses,
annual revenues, and ownership patterns) and the availability of capital for future growth. To
predict changes in the kinds of economic activity that would occur with the project, it is
necessary to describe the kinds of goods and services that would be required by the project or
associated workforce and determine whether they are provided locally or imported. Unique
features of the business community such as high seasonality, high outflow of profit, declining
trade, or downtown revitalization should also be included.
Land Use
A description of land use should identify the current use of land needed specifically for the
facility, its system components, its safe area, and its residuals, and land use patterns in the
nearby area that will be indirectly affected by the project. Particular emphasis should be placed
on land uses that pose potential conflicts for large-scale industrial activity — residential areas,
agricultural lands, woodlands, wetlands — and on the local or regional zoning laws that may
limit the development of industry or commercial activities on which it relies.
Aesthetics
Aesthetics involve the general visual, audio, and tactile environment (imagine the sensory
differences among urban, industrial, agricultural, and forest environments). A description of
the aesthetic characteristics of the existing environment should include things that are seen,
heard, and smelled in and around the site and their emotional or psychological effect on people.
Descriptions (or pictures) of views of the site, of unique features or features deemed of special
value, and public use and appreciation of the site provide information that must be available for
the assessment of impacts.
Cultural Resources
Cultural resources encompass several areas relating to man's knowledge and appreciation
of prehistoric and historic events. The location of a facility at or near significant historical and
cultural sites tend to degrade their resource value or emotional impact. The location of the
following kinds of sites should be described in relation to the project site:
• Archeological sites (where man-made artifacts or other remains dating from prehistoric
times are found);
• Paleontological sites (where bones, shells, and fossils of ancient plants or animals are
found in soil or imbedded in rock formations);
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Affected Environment
Historic sites (where significant events happened or where well-known people lived or
worked);
Sites of particular educational, religious, scientific, or cultural value.
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Environmental Consequences
8. ENVIRONMENTAL CONSEQUENCES
The "Environmental Consequences" section forms the scientific and analytical basis for. the
comparison of alternatives. It contains discussions of beneficial and adverse impacts of each
reasonable alternative and mitigation measure (40 CFR Parts 1502.16 and 1508.8) including:
(a) Direct effects and their significance — direct effects are caused by the proposed action
and occur at the same time and place.
(b) Indirect effects and their significance — indirect effects are those caused by the action
but are later in time or farther removed in distance, but are reasonably foreseeable.
This also includes growth effects related to induced changes in the pattern of land use,
population density, or growth rate and related effects on air, water, and ecosystems.
(c) Possible conflicts between proposed actions and the objectives of federal, regional,
-state, local and ... tribal ... land use plans, policies, and controls for the area
concerned.
(d) The environmental effects.
(e) Energy requirements and conservation potential.
(f) Natural or depletable resource requirements and conservation potential
(g) Urban quality, historical and cultural resources, including reuse and conservation
potential.
(h) Means to mitigate adverse environmental impacts not fully covered by the alternatives.
The potential impacts of each alternative are identified by a systematic disciplinary and
interdisciplinary examination of the consequences of implementing each alternative.
Methods of Analysis
While information may be gathered from new source NPDES applications, EIDs, and other
sources, EPA is responsible for the scientific and professional integrity of any information used
in an EIS. The applicant's EID and other sources of data, therefore, must clearly explain all
sources, references, methodologies, and models used to analyze or predict results. Applicants
should consider the uses and audiences for their data and EPA's affirmative responsibility in
using them. EPA has the same responsibility in the use of data submitted by other agencies,
private individuals, or groups.
Each impact has its own means of identification, qualification, and quantification. For
example, air quality impacts are modeled using standard state- or federally-approved programs.
These numerical models depend on standardized parameters and site-specific data. Stationary
source emissions from plant operation as well as mobile emissions related to traffic circulation
from induced employment or growth all contribute to air quality impact quantification. The goal
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Environmental Consequences
is to quantify impacts on air quality, water quality, employment, land use, and community
services — categories that lend themselves to numerical calculations, modeling, and projections.
Some environmental elements like aesthetics lend themselves to more qualitative or graphic
analyses.
Biological impacts frequently are not readily quantifiable because absolute abundance of
individual species are difficult to determine. Impacts may be described as acres of habitat lost
or modified or to qualitative impact descriptions of population changes in major species or'
species groups. The key in the Environmental Consequences section is to clearly and succinctly
lead a reader through each impact identification, qualification and/or quantification. Detailed
methodologies or extensive data can be incorporated by reference if the source is readily
obtainable. Materials from applicants must carefully follow-this pattern to facilitate validation
and incorporation in the EIS. General impacts likely to occur with new source facilities are
identified in later sections along with suggestions on the kinds of information needed to analyze
data and draw conclusions.
Determination of Significance
The term "significant effect" is pivotal under NEPA, for an EIS must be prepared when a
new source facility is likely to cause a significant impact. What is significant can be set by law,
regulation, policy, or practice of an agency; the collective wisdom of a recognized group (e.g.,
industry or trade association standards); or the professional judgment of an expert or group of
experts. CEQ (40 CFR Part 1508.27) explains significance in terms of context and intensity of
a action. Context relates to scale — local, regional, state, national, or global; intensity refers
to the severity of the impact. Primary impact areas include affects on public health and.safety,
and unique characteristics of the area (e.g., historical or cultural resources, parks, prime farm
lands, wetlands, wild and scenic rivers, or ecologically critical areas). Other important factors
include:
• Degree of controversy over effects of human encroachment
• Degree of uncertain or unknown risks
• Likelihood a precedence .will be set
• Occurrence of cumulative impacts (especially if individually not significant)
• Degree to which sites listed, or eligible for listing, in the National Register of Historic
Places may be affected
• Degree to which significant scientific, cultural, or historical resources are lost
• Degree to which threatened or endangered species or critical habitats are affected
• The likelihood of violations of federal, state, regional or local environmental law or
requirements.
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In its new source NPDES program, EPA's environmental review procedure (40 CFR Part
6.605) indicates that the responsible officer shall consider short- and long-term effects, direct
and indirect effects, and beneficial and adverse effects. The published specific criteria identify
some of the natural and man-made environmental elements whose significant impact would
trigger the preparation of an EIS. According to the regulations, an EIS will be prepared when:
(1) The new source will induce or accelerate significant changes in industrial, commercial,
agricultural, or residential land use concentrations or distributions which have the'
potential for significant environmental effects. Factors that should be considered in
determining whether these changes are environmentally significant include but are not
limited to:
- The nature and extent of the vacant land subject to increased development pressure
as a result of the new source;
- The increases in population or population density which may be induced and the
ramifications of such changes;
- The nature of the land use regulation in the affected areas and their potential effects
on development and the environment; and
- The changes in the availability or demand for energy and the resulting
environmental consequences.
(2) The new source will directly, or through induced development, have significant adverse
effects upon local ambient noise levels, floodplain, surface or groundwater quality or
quantity, fish, wildlife, and their natural habitats.
(3) Any major part of the new source will have significant adverse effect on the habitat of
threatened or endangered species on the Department of the Interior's or a state's list
of threatened and endangered species.
(4) The environmental impacts of the issue of a new source NPDES permit will have
significant direct and adverse effect on property listed in the National Register of
Historic Places.
(5) Any major part of the source will have significant adverse effects on park lands,
wetlands, wild and scenic rivers, reservoirs, or other important bodies of water,
navigation projects, or agricultural lands.
With the regulations in mind, it is ultimately up to EIS preparers to make judgments on what
constitutes a significant impact. The threshold of significance is different for each impact, and
those making the judgments need to explain the rationale for the thresholds chosen. Clear
descriptions of the choice of the threshold of significance provides a reviewer with a basis for
agreeing or disagreeing with the determination of significance based on specific assumptions,
criteria, or data. Sometimes the thresholds are numerical standards set by regulation. In other
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cases, the thresholds may be set by agency practice (e.g., the U.S. Fish and Wildlife Service
may consider the potential loss of a single individual of an endangered species as a significant
impact), or the EIS preparer's professional judgment determines the rationale for the threshold.
The NPDES permit applicant may suggest a threshold for each impact in the EID, but it is
critical to carefully define how and why each particular threshold was chosen and applied.
Comparisons of Impacts under Differing Alternatives
Alternatives may be compared in several different ways. All the impacts associated with
a single alternative may be examined together and summarized in a final list of significant
unavoidable impacts, or the like impacts of all the alternatives can be determined and compared
within a final summarized list of significant unavoidable impacts. The choice of approach should
be determined by the EIS preparers based on the approach that would provide the most clear,
concise evaluation for decision makers and reviewers. The summary information on possible
impacts and mitigation measures is usually prepared in tabular form and included in the
executive summary. Examples of formats that can be used are found in standard environmental
assessment technology texts, agency manuals, EISs, and similar documents.
Summary Discussions
CEQ and EPA NEPA guidelines describe the expected general contents of the section called
"Environmental Consequences." In addition to identifying, quantifying, and comparing the
impacts of each alternative, 40 CFR Pan 1502.16 specifies that discussions will include "...any
adverse environmental impacts which cannot be avoided should the proposal be implemented,
the relationship between short-term uses of man's environment and the maintenance and
enhancement of long term productivity, and any irreversible or irretrievable commitments of
resources which would be involved in the proposal should it be implemented."
Over the last 20 years, these three topics have been included as a separate chapter(s) in draft
EISs along with chapters called cumulative impacts, adverse effects which cannot be avoided,
or residual impacts and mitigation. No matter what format is used with these topics, they often
receive only cursory treatment. Such a practice is unfortunate because these long term, larger
scale issues are those that affect overall environmental quality and amenities. The important
point is not the location of these topics in the document, but the need to present data and
analytical procedures used to qualify and quantify these concerns.
A section called cumulative impacts can be addressed in several ways. Some EISs consider
cumulative impact sections to be summaries of all residual impacts for each alternative. They
may also include any synergistic effects among impacts. A second, and more helpful, approach
to cumulative impacts reflects a broad view of environmental quality and suggests how impacts
of the proposed project or alternatives contribute to the overall environmental quality of the
locale. In this approach, the impacts of the new source project are considered in relation to the
impacts associated with projects approved, but not constructed; projects being considered for
approval; or planned projects. This "accumulating" impacts approach to cumulative impacts is
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particularly instructive when no single project is a major cause of a problem, but contributes
incrementally to a growing problem.
All of these summary topics focus on broad views and long time lines in an attempt to put
project impacts in perspective. The data requests from EPA to applicants must specify the
environmental setting and consequences data needed to qualify and quantify the potential impacts
and put each potential impact in perspective in terms of local, regional and perhaps state or
national environmental quality. The question to be answered is: what part do the project-related
impacts play in local/regional/state/national environmental quality now and in the future for each
affected parameter.
Mitigation Measures
Early in the history of NEPA, emphasis was placed on identifying mitigation for all possible
impacts conceivably associated with a project or its alternatives. Now the emphasis is on
avoiding and minimizing potential impacts long before a NEPA document is prepared. This is
accomplished by refining the proposed project and alternatives during siting, feasibility, and
design processes. The goal is to have project alternatives with as few significant impacts as
possible.
CEQ NEPA regulations define mitigation (40 CFR Part 1508.20) to include:
(a) Avoiding the impact altogether by .not taking a certain action or parts of an action.
(b) Minimizing impacts by limiting the degree or magnitude of the action and its
implementation.
(c) Rectifying the impact by repairing, rehabilitating, or restoring the affected
environment.
(d) Reducing or eliminating the impact over time by preservation and maintenance
operations during the life of the action.
(e) Compensating for the impact by replacing or providing substitute resources or
environments.
This listing of mitigation measures has been interpreted as a hierarchy with "avoiding
impacts" as the best mitigation and "compensating" for a loss as the least desirable (but
preferable to loss without compensation). This hierarchy reinforces the present approach of
trying to avoid or minimize potential impacts during project siting and design. The goal is to
have the most environmentally sound project and alternatives to carry into the impact assessment
process of NEPA.
Even with the best project siting and design, there will be environmental impacts associated
with each of the alternatives. For the impacts, especially for the impacts judged to be significant
impacts, mitigation measures need to be suggested.
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The first source of possible mitigation measures should be those offered in an applicant's
BID. Each mitigation,measure should be described in enough detail so that its environmental
consequences can be evaluated and any residual impacts clearly identified.
The proposed project and its alternatives — or the suite of alternatives if there is no
preferred alternative — typically reflects choices among tradeoffs. The tradeoffs can include
different sites, processes, pollution control technologies, costs, or other features. Typically the
tradeoffs are complex for new source facilities with dissimilar beneficial and detrimental impacts
among the alternatives. The analysis should be deemed complete if:
(1) the alternatives brought forward for analysis are all reasonable;
(2) all possible refinements and modifications for environmental protection have been
incorporated in the alternatives; and
(3) any residual impacts and consequences of mitigating those impacts have been
evaluated.
Decision makers are then confronted with comparing the alternatives based on tradeoffs,
often requiring value judgments.
General Impacts
The rest of this chapter on environmental consequences is organized into two major sections.
The first presents information on the impacts associated with facility construction and operation
from a general point of view. In this section, specific impacts that may be caused by new
source facilities are outlined, without reference to specific processes or activities associated with
different industries. The second section covers industry-specific impacts — those impacts that
result from the kinds of facilities covered in this guidance.
New source facilities are often large and frequently cover hundreds of acres of land.
Facility operation requires a sizable infrastructure including internal transportation networks for
raw material and product transport, loading and unloading areas, fuel and raw material storage
areas, production facilities, waste control and treatment facilities, and waste storage or disposal
areas.
Because of the large land area required for these facilities and the diversity of activities
required to operate them, there are a range of impacts that essentially cannot be avoided. The
most noticeable impacts are associated with site preparation and construction — the changing of
one land use to another — but there are also ongoing and indirect impacts associated with facility
operation that should be covered in an environmental impact assessment.
The general impacts associated with new source facilities are discussed in the following two
sections. The first section covers impacts associated with site preparation and construction; the
second with facility operation.
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Impacts from Site Preparation and Construction
Site preparation and construction for large, complex facilities includes some degree of land
leveling and soil compaction and the erection of production facilities, raw material loading and
unloading areas, raw material storage areas, waste storage and disposal areas, and a
transportation system for moving materials from one area to another. In the first stage of
construction activity, land is cleared and prepared for the storage of building materials, for
transporting materials between the storage areas and building sites, and for the building sites'
themselves. For very large facilities, stone crushing, concrete mixing, and other materials
processing facilities may also be built on-site. These activities affect the immediate area in
predictable ways. The impacts associated with site preparation and construction are discussed
below under the following headings:
• Habitat alteration
• Pollutant generation
• Socioeconomic impacts.
Habitat Alteration
The extent to which habitats are affected by site clearing and grading depends on the extent
to which natural ecosystems were previously disturbed. Conversion of a wooded and previously
undisturbed area results in greater changes than conversion of a previous industrial site. The
habitats associated with heavily vegetated areas are almost always more plentiful and diverse
than those associated with previously used sites.
The majority of habitat impacts stem from clearing and grading land. The removal of native
vegetation has a direct effect on some species by removing their protective cover, food sources,
or roosting, nesting, or breeding sites. It can have indirect effects on others by exposing bare
soil, which is more subject to erosion, leading to sedimentation in a nearby waterbody,
smothering habitat used by aquatic plants and animals. The removal of vegetation and
compaction of soils by construction machinery also increases the rate of runoff following rain,
increasing the volume of water that must be carried by local streams, and increasing the rate of
stream bank erosion and habitat smothering. The removal of shade over streams also increases
water temperatures, sometimes reducing the value of the stream for cold water species of fish.
Even if natural habitats are not completely destroyed, by clearing and grading, they may lose
their value for some species because they become fragmented. Some species require a minimum
size of a particular habitat type in order to survive. If the habitat is broken up, even if only by
a road, the size of the available habitat type may be sufficiently reduced to prevent their
continued survival, and they leave the area or succumb.
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Critical Issues:
• Will construction and site preparation activities alter critical habitats for wildlife
impacting the local presence of such species?
- Quantify areas and locations of habitats and associated species that would be lost or
adversely affected during site preparation and construction activities.
i
• Would indirect changes in habitats following construction and site preparation activities
occur? e.g., increased erosion potential resulting in habitat disturbance through
sedimentation in waterbodies; disturbance of habitat and/or species from increased human
access; accumulation of pesticides or construction chemicals in some habitats, and thence
in wildlife and vegetation, etc.
- Identify activities that would indirectly alter habitats. Quantify, to the extent feasible,
the areas that would be indirectly affected.
Pollutant Generation
The most significant pollutants associated with site preparation and construction are dust and
sediment resulting from land clearing. Dust and sediment may also be associated with toxic
chemicals that tend to adsorb to panicles. Dust tends to be a local annoyance, but can also
blanket the vegetation in nearby areas, sometimes reducing its viability. Sediment from the site
causes increased turbidity in nearby water bodies and may be deposited on stream bottoms,
altering the nature of the substrate and changing stream bottom fauna from hard bottom or riffle
communities to soft bottom communities. If the stream bottom community is changed, there will
also be changes in the species of fish inhabiting the stream.
Uncontrolled construction site sediment loadings have been reported to be on the order of
35 to 45 times greater than loadings from undisturbed woodlands (typically less than 1 ton per
year; Novotny and Chesters, 1981). In addition to disrupting stream bottom habitats as
described above, the increased levels of turbidity also affect aquatic resources by reducing light
penetration, and in turn reducing plant production in receiving waters.
Critical Issues:
• Would water quality-be degraded by increased surface runoff (sediment and pollutant
discharges), discarded or discharged construction materials and other chemicals,
herbicides, wastewater, soil additives, disturbance of stream bed, or temperature increases
due to increased turbidity or removal of vegetation?
- Characterize sediment loading and compare loadings and predicted in-stream
concentrations of associated pollutants with existing federal, state, and local water
quality standards and criteria.
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• Would there be increased overland flow, storm runoff, flood potential, stream bed
sedimentation, or channel erosion due to increased runoff following site preparation and
construction activities?
- Determine the extent of stream damage caused by increased runoff (i.e., increased
stream bed sedimentation, channel erosion).
• Would dust or air pollutants be generated from construction and site preparation
activities?
- Identify emission sources and project emission rates. Compare these rates to applicable
federal, state and local standards and limitations (both emissions and air quality);
compare predicted atmospheric levels with federal, state, or local standards.
Socioeconomic Impacts
In addition to the environmental impacts described above, the construction of new source
facilities affects the local socioeconomic framework in many ways. These effects can be
categorized as: (1) the compatibility of new land uses with existing land uses; (2) issues
associated with human and institutional resources and impacts on community structure; and (3)
effects on the local economy. Many of these impacts are initiated in the site preparation and
construction phase, but they can continue in varying forms throughout the period the facility
operates.
Land Use Change
Site preparation for the construction of new source facilities disturbs large areas of land and
may change patterns of land use in the area. Open spaces (agricultural land, forested areas,,or
other vacant land) are often used for these facilities. Regardless of the land use of the original
site, construction of these facilities disturbs large tracts of land and converts them to a new use
that may not be compatible with, nor easily returned to, its original state. Industrial sites are
not easily converted back to either forest, agricultural, or residential land. Thus the decision
to build a facility at a particular, site is essentially irreversible. .Once construction has begun,
the options for converting the site to other land uses become limited.
There are also changes in land use in the surrounding area. Housing is needed for the large
construction crews required for these facilities, and construction workers generally prefer to live
near the facility site. If the site is in a predominantly residential area, then housing will not
necessarily be a problem (although housing values may decline if an industrial site is to be
located in close proximity). If the site is far from a residential area, however, additional
housing, often in the form of trailer parks, may develop in the immediate vicinity. In addition,
small-scale commercial areas tend to develop around construction sites to provide food and
sundries for workers and to provide construction support services.
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Critical Issues:
• Would the construction and site preparation activities be compatible with the projected
uses of adjacent, existing, or planned land uses. Is the site located in an area with
existing or planned industrial facilities, or would the facility result in adverse aesthetic
impacts or conflict with current or future residential, agricultural, or other land uses?
- Identify the amount of existing or planned land use areas lost due to site preparation
and construction activities. Describe expected changes in land use on nearby land.
• Does existing land availability, as determined by zoning and land use plans, conflict with
site preparation and construction activities?
- Determine to what extent zoning requirements and current land uses conflict with the
facility site preparation and construction activities.
Human and Institutional Resources; Community Structure
The development of complex new facilities often generates extensive changes in the
community structure of an area; many of these changes stem from changes in employment
patterns. Construction of major facilities requires a large, trained work force that is often not
locally available. Construction tends to attract workers from outside the immediate area. This
influx of workers may not be significant in large and diverse communities, but in small
communities, the entire economy can be changed, causing changes in employment patterns,
population and population density, and housing, with implications for the adequacy of
community services. If the facility requires a large work force during the operational phase,
then these changes, usually temporary, could become permanent.
In small communities, the support of a large population of construction workers may require
an expansion in community-provided services. Water supply, sewerage systems, and streets and
roads might need modification or expansion. This expansion in community services can extend
the environmental impacts associated with a new facility to other locations where new water
treatment plants or streets and roads are needed. The construction of a new facility thus could
contribute to changes in environmental quality that extend far beyond the immediate boundaries
of the site. ,
The expansion in the labor force associated with new facility construction typically requires
a buildup of support resources. Unfortunately, the number of people required to operate the new
facility are often less than those required to construct it. Therefore, the influx of people could
be temporary unless the community or larger geographic area has taken measures to
accommodate displaced workers upon project completion. Depending on the success of the
surrounding area to accommodate these people, there could be a withdrawal of workers from
the area and a reduced need for the additional services that were once developed to accommodate
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them. This could negatively affect local economies, and in a worse-case scenario, entire areas
(e.g., employee housing) could be abandoned.
Critical Issues:
• Would existing housing, community services, and infrastructure support a large temporary
workforce during the site preparation and construction? What will happen to increased
services after the site preparation and construction activities cease?
- Identify the amount of deficient housing, community services, and infrastructure for
the increased workforce during site preparation and construction. Determine services
that will not be necessary after construction and site preparation cease.
• Is there a possibility of employment pattern changes from construction and site
preparation activities? For example, will the area have increased employment and income
directly and indirectly attributable to construction of the facility? Will construction of the
, facility compete with other projects or existing sources of employment for workers?
- Determine the extent of changes in employment patterns attributable to site preparation
and construction activities.
• Would there be a change in the community structure during and after site preparation and
construction activities? Would the community life-style, structure, and stability be
affected? Would there be difficulty in attracting professionals during and after'
construction? Would government jurisdiction(s) have difficulty accommodating changes
in community structure?
- Determine the extent of community structure changes caused by site preparation and
construction activities.
• Are transportation facilities adequate for site preparation and construction activities?
Would traffic congestion result?
- Identify the transportation facilities -needed for site preparation and construction
activities; determine shortfalls in capacity.
• Would site preparation and construction activities present health and safety hazards to
humans working on or near the site? e.g., increased possibility of accidents associated
with the use of explosives or heavy equipment; exposure to noise from construction
activities posing a health hazard.
- Identify health and safety hazards to workers and the public due to site preparation and
construction activities.
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Loss of Historic or Cultural Resources
Just as clearing and grading activities remove existing vegetation and alter natural habitats,
the same activities may affect historical, archaeological, or cultural resources. Site clearing
activities may inadvertently collapse or undermine the structural integrity of archeological sites,
or the facility might be built on an historical site. Even if these sites are preserved, their
historical or archeological significance may be irrevocably damaged through the nearness of
industrial activity.
Critical Issues:
• Would historical or cultural resources on the site be disturbed, destroyed, or covered over
by site preparation and construction activities?
- Identify historical and cultural resources destroyed or disturbed by site preparation and
.construction activities; include discussion of any mitigation necessary to preserve items
of archeological, historical, or cultural interest.
Impacts from Facility Operation
\
This section presents information on the general impacts likely to be caused by facility
operation. Topics are covered according to headings usually found in EISs — air quality, water
quality, etc. — to facilitate review of EIDs. In general, the impacts associated with facility
operation are not as severe as those associated with construction. Facilities cannot operate
without obtaining permits for water discharges and air emissions, for example, and most permits
are issued only after it is determined that environmental impacts will be acceptably small.
Nevertheless, there are impacts that should be analyzed in an EID, and these are presented
below. r
Air Quality
New source facilities impact air quality through atmospheric emissions of particulates,
hydrocarbons, carbon monoxide, carbon dioxide, sulfur oxides, and nitrogen oxides.
Particulates result in a "dirty" or "dusty" atmosphere and accumulate on surfaces. Toxic
chemicals also attach to particulates resulting in potential human health impacts if inhaled, and
accumulation of toxic chemicals on land surfaces may cause environmental health impacts.
Hydrocarbons and carbon dioxide are chemicals which are primarily responsible for the
"greenhouse effect," by preventing the back radiation of heat from the earth's surface, increasing
the temperature of the atmosphere. Carbon monoxide is a known toxicant, causing neurological
and lung disorders, and even death. Sulfur oxides and nitrogen oxides are "acid rain"
constituents, which, when dissolved in rain droplets, lower the pH of natural waterbodies, and
destroy natural and man-made materials and structures. Emissions can also produce obnoxious
odors affecting large areas in the vicinity of the site.
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Air quality impacts can be determined quantitatively by comparing new source facility
emissions with emission standards set by federal, state, or local governments, and by comparing
the expected ambient concentrations of pollutants caused by facility emissions and other sources,
with ambient concentration standards. EPA-approved models that should.be used for these
projections are discussed under industry-specific impacts.
Critical Issues:
• Will facility operations result in non-compliance with air emission and ambient air quality
standards?
- Identify emission sources and rates, including sources in the vicinity not associated
with the site, and determine expected concentrations of pollutants in air. Compare
emission rates and resulting concentrations to applicable federal, state, and local
standards and limitations.
• Would stack emissions from the facility have deleterious effects on visibility and light
scattering (i.e., cause smog?); damage natural or man-made materials and structures (i.e.,
cause acid rain?); adversely affect human health, domestic animals, wildlife, or
vegetation?
- Characterize stack emissions during operation and maintenance activities and compare
with existing federal, state, and local standards.
Water Quality
i
Impacts to water from new source facilities range from water quality degradation from
discharged toxics to hydromodification changes associated with increased impervious area, soil
exposure, and erosion. Pollutants may enter surface waters from wastewater disposal to land,
effluent discharges, or precipitation runoff from raw material or product storage areas.
Nutrients (nitrogen and phosphorus compounds) in water can lead to eutrophication—excess plant
growth resulting in algal blooms, weed-choked waterbodies, and fish kills. Toxic contaminants
result in acute and chronic toxicity to aquatic biota as well as possible human health affects with
ingestion of contaminated water. The temperature regimes of receiving waters may be changed
through warm water effluents. Increases in ambient temperatures generally reduce biodiversity
and limit the abundance of cold water fish species. The possibility of water quality impacts can
be determined by modeling the concentrations of contaminants in receiving waters caused by
process and stormwater discharges, and comparing the results with water quality standards.
EPA-approved models that can be used for this purpose are found in the industry-specific
impacts section.
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Critical Issues:
• Will toxic pollutants and/or organic matter from wastewater disposal, effluent discharges,
or precipitation runoff from storage areas have deleterious effects on groundwaters or
surface waters?
- Model pollutant concentrations in groundwaters and surface waters and compare with
existing federal, state, and local water quality standards and criteria.
• Would the facility cause adverse environmental impacts to the receiving water body?
- Estimate the discharge plume's short and long • term impacts to the biological
community.
• Would there be a change in the temperature of receiving waters because of heated
effluents?
- Predict receiving water temperature distributions around and below cooling water
discharges. Compare results with federal, state, or local standards.
• Would facility operation cause increased sedimentation and habitat destruction by altering
the existing flow patterns of water courses?
- Determine which aquatic habitat might be impacted, and to what extent.
Soil Quality
The majority of the impacts to soils occur during site preparation and construction. As
enumerated in the previous section, these include: soil loss due to the removal of top soil during
the clearing and grading process; soil compaction and erosion; reduction in the productive
capacity (i.e., fertility) of the soil; potential soil contamination; and a general loss of soil
resources due to coverage by impervious areas.
After plant operations begin, the potential for soil contamination is high in raw
material/product loading and unloading areas, materials storage areas, and/or in production areas
of the facility where spills may occur. The potential for soil contamination is also high in areas
used for on-site waste storage or treatment facilities. Frequently land treatment units or landfills
are used; sometimes waste materials are stored in piles (e.g., ash piles). Contaminant runoff
or leachate from these areas can percolate through soils to groundwater.
In addition to the potential for soil contamination during the operating phase of the facility,
soil erosion and sedimentation can still occur. The extent of the problem depends on the
effectiveness of the erosion control techniques used to stabilize the site after construction,
especially on steep slopes and/or areas that are allowed to remain without vegetative cover.
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Critical Issues:
• Would there be decreased soil permeability due to compaction from operation and
• maintenance activities? Are there indirect and direct losses of soils through erosion
caused by improper protection of exposed soils?
- Determine the potential for soil loss during facility operation. Discuss mitigation
activities to be used to reduce erosion.
Vegetation
As described earlier, construction of new source facilities removes much of the vegetative
cover. The impacts associated with these actions vary, depending on the site, but can be
particularly acute if environmentally-sensitive or ecologically-important areas are affected (e.g.,
wetlands, riparian zones). In most cases, this lost natural vegetation is not replaced, either
because so much of the area is rendered impervious, or because the land is disturbed to a point
that it will no longer support native vegetation. Often, the replanting that does occur is done
for aesthetic purposes; land is converted to turf grass, or ornamental landscaping plants are used.
While attractive, these non-native vegetative covers do not offer the same level of environmental
protection, nor ecological value of the natural vegetation.
The absence or scarcity of vegetation removes or reduces pollutant buffering capacity of the
site, contributing to some of the following impacts:
• Increased potential for pollution, especially water pollution as runoff will be enhanced
(volume and velocity) and can enter water bodies directly without the filtering effects of
vegetation.
• On site conditions can be more severe, with wider temperature fluctuations, higher noise
levels, and greater winds generating dust.
• Probable reduction in the numbers of species and abundance of wildlife species
composition.
Critical Issues:
• Would there be permanent loss or displacement of vegetation habitat, and therefore floral
species (rare, endangered, unique or unusual species, communities or habitats) because
of the facility?
- Identify critical habitats and associated species which would be not be restored
following facility construction. Rare, endangered, unique or unusual species, as well
as ecosystems, communities and habitats should be included within the assessment.
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• Would changes in species composition, diversity, and number occur in the vicinity of the
facility?
- Identify changes in local species composition, diversity, and number resulting from loss
of specific types of habitats.
• Would air and water quality degradation from toxics produced during operation and
maintenance activities pose hazards to area flora (resulting in death, illness, reduced
reproduction, etc.)?
- Determine the extent of hazards to vegetation from air and water quality degradation.
Wildlife
The impacts to wildlife are primarily associated with changes that occurred during site
preparation and construction. However, many of the impacts are carried over into the
production phase and remain throughout the life of the facility. Habitat restoration is often
impossible during operations because of irreversible, damage done to soils and topography and
the construction of buildings, roads, and storage areas.
As described previously in this section, the habitat loss associated with vegetative removal
can have many far-reaching effects ranging from direct impacts on species depending on the
removed vegetation to indirect impacts, such as water quality degradation and stream habitat
damage resulting from the changing site conditions associated with site denudation. All of these
impacts affect the food supplies and living conditions of countless species, ranging from the
smallest microbes to large animals. Food sources may be destroyed, modified, or contaminated;
nesting and breeding locations obliterated; ranges fragmented; and travel/migration routes
irrevocably altered by the activities and infrastructure involved in constructing and operating a
new source facility. All of these conditions affect the composition, distribution, abundance,
health, and vitality of species.
Critical Issues:
• Would there be permanent loss or displacement of wildlife habitat, and therefore faunal
species (rare, endangered, unique or unusual species, communities or habitats) because
of the facility?
- Identify critical habitats and associated species which would be lost during construction
and not replaced during facility operations. Rare, endangered, unique or unusual
species, as well as ecosystems, communities and habitats should be included within the
assessment.
• Would change in species composition, diversity, and number occur in the vicinity of the
facility?
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- Identify changes in local species composition, diversity, and number caused by human
activity.
• Would air and water quality degradation from toxics produced during operation and
maintenance activities pose hazards to area fauna (resulting in death, illness, reduced
reproduction, etc.)?
- Determine the extent of hazards to wildlife from air and water quality degradation.
• Would operation and maintenance activities restrict migration routes and daily movement
corridors or disturb sensitive species from human encroachment?
- Identify migration routes and movement corridors of sensitive species disturbed by
facility operation.
• Is there a potential for mechanical damage to biota from water intake structures during
operation and maintenance activities?
- Predict the extent of mechanical damage to biota from water intake structures.
Environmental Health and Safety
The large size and complex array of operations that comprise new source facilities pose
threats to the health and safety of workers and the general public. Some of the threats occur
during the construction phase, but health and safety issues tend to be more prevalent during
facility operations. The three biggest areas of health and safety concerns are industrial
accidents, exposure to contaminants, and noise.
As described in the technology overview section of this document, many hazardous or
potentially dangerous materials are used or manufactured directly by petroleum refineries and
coal gasification facilities. Others are created as byproducts. Plant workers* have frequent
exposure to these materials, either through direct handling or exposure to fugitive dust and other
air emissions, or from spills and accidents. The potential for accidents at these facilities is fairly
high, as large quantities of raw material inputs must be used (and transported) around the facility
and large volumes of waste are generated and must be handled during disposal.
Noise is a particularly challenging problem at these facilities. For example, in the case of
petroleum refineries, sources of noise include high speed compressors, control valves, piping
systems, turbines and motors, air cooled heat exchangers, and other cooling devices. These
sources create noise levels that range from 60 to 110 dBs at a distance of one meter from the
source (The World Bank, 1991); these levels may be high compared to U.S. Occupational Safety
and Health Administration requirements.
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Critical Issues:
• Would operation and maintenance activities present health and safety hazards to humans
working on or near the facility site? Examples might be an increased possibility of
accidents associated with the use of operation and maintenance equipment; exposure to
emissions from operation and maintenance activities presenting a health hazard; or
exposure to noise from operation and maintenance activities posing a health hazard.
- Identify health and safety hazards to workers or the nearby public due to operation and
maintenance activities.
Land Use
The presence of a new source facility in an area affects land use not only during construction
(see previous section), but also after construction is complete. The major impact on land use is
the conversion of nearby land from agricultural or other use to industrial use for supporting
facilities or residential use to meet the needs of an expanded labor force. Unless the area is
already industrialized, introduction of one of these facilities changes the character of the nearby
land uses — open space will be reduced and population densities may increase.
Critical Issues:
• Do land use requirements for operation and maintenance activities (safe zone or buffer
zones included) conflict with adjacent present or future land uses as planned by local,
regional and state agencies?
- Identify the amount of existing or planned land use areas lost due to operation and
maintenance activities.
• Will induced growth around the facility change land use in ways that are counter to
currently planned land uses for the area? Will the mix of land in the vicinity be
irrevocably altered because of the facility?
- Describe anticipated changes in nearby land use as a result of the facility, Evaluate
potential conflicts, not identified during the construction phase, that would occur during
operations.
Visual Resources
Just as land uses change due to the introduction of a large industrial facility, so do visual
resources. Again, the extent of impacts depends on the condition of the visual resource prior
to facility construction and how compatible new land uses are with old. The impacts to visual
resources will be large if the new facility is located in a previously undisturbed or scenic area
(e.g., near a national park).
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Visual resources can be important in a cultural, historic, aesthetic, and psychological
context. Because of the large size of new source facilities and the diverse array of structures
and storage areas associated with them (e.g., items ranging from large buildings and stacks to
tank .farms and piles of coal or ash), the nature of the landscape can greatly change as a result
of their introduction. The presence of these facilities can not only affect an area's viewshed,
but also its natural topography (through extensive grading, presence of large waste piles),
thereby changing the entire character of an area.
Critical Issues:
• Will facility operation alter or disrupt visual amenity of the area or other aesthetic
attributes of the site?
- Determine the extent to which operation and maintenance activities disrupt sensory
attributes.
• Would facility operations provide for an aesthetically satisfactory work environment?
- Determine if the facility components are designed with consideration given to human
factors.
Cultural Resources
The impacts to cultural resources that occur during facility construction remain after
operations begin: Although the National Historic Preservation Act requires mitigation of impacts
to these resources, the success of these techniques is varied. Also, regardless of mitigation
techniques used, the presence of a major industrial facility around a significant historical site
removes that resource from its natural context and is likely to reduce its overall significance.
Critical Issues:
• Would the value of a mitigated cultural or historical resource be reduced because of the
presence of the facility? .
- Identify historical and cultural resources that would be reduced in value by the
presence of the facility, especially if impacts were mitigated.
Socioeconomic Impacts
As described in the previous section, many socioeconomic changes occur during the
construction phase of new source facilities. These impacts are primarily related to the influx of
a large, temporary workforce. Depending on the facility size, the number of workers required
for plant operation may be comparable to, or much lower than, those required during the
construction phase. If the work force is greatly reduced, reduced economic opportunities,
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down-sizing, and even recession may result because the service sector that was created to
support the construction labor force lost its market. On the other hand, if the labor force
remains constant, or increases, an enhanced economy can result from the influx of dollars spent
on local products and services and an increased local tax base. As well, the presence of a new
facility could attract additional businesses, and other support services, thereby, continuing to
provide positive economic enhancements to the area. In the short term, the local infrastructure
could be strained, but in the long term, development (perhaps even a shift to increased
urbanization) is likely occur.
Although in many ways the presence of a large facility can induce positive changes to a local
economy, it can also create negative impacts. Most apparent of these is the increased likelihood
of environmental degradation associated with expansion. But also, some areas may suffer
financially, as the presence of a big industry could drive down real estate values.
Critical Issues:
• Will the housing, community services, and infrastructure support required for supporting
a large temporary construction workforce be necessary during plant operations? Will
infrastructure development costs be able to be borne by the permanent workforce?
- Identify any excess housing, community services, or infrastructure that would not be
necessary during facility operation.
• Will facility operation cause increased or decreased employment and income, both direct
and indirect, over the construction phase? Will the facility compete with other projects
for employees?
- Determine the extent of employment pattern changes attributable to changes from
facility construction to operation.
• Will additional infrastructure or community services be required to support facility
operation?
- Identify the types and amounts of infrastructure or community services that are
required to support facility operation.
Technology-Specific Potential Impact Reduction
i
The following sections discuss the technologies and other pollution control activities used
by petroleum refineries and coal gasification facilities.
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Mitigating Impacts in Project Design
There are a number of pollution control measures that can be applied in the design phase
to effectively reduce waste streams and their associated environmental impacts. Many of these
steps also reduce operation and capital costs and/or increase production. The EID should
contain a discussion of the waste management alternatives considered and their applicability.
Discussions of pollution control should include descriptions of effluents, emissions, source
reduction, reuse and recycling options.
The maintenance activities required for optimum operations are partially defined during the
design phase as well. Effective maintenance measures can also reduce waste streams. The
applicant should describe proposed maintenance activities with potential inherent impacts in the
EID.
Pollution control equipment and systems are expected to be designed into the refinery
process and waste treatment operations. These measures can effectively reduce adverse impacts
by the emissions and wastes that are generated. However, these systems may create other kinds
of impacts, by creating more concentrated, smaller volume wastes, or by converting wastes to
other compounds. Often a residual solid or liquid waste is generated. As examples, H2S
removal in a waste gas stream may leave other SOx compounds in the exhaust, and waste
treatment systems for aqueous streams may not have the ability to treat all of the complex
organic compounds which may be in the wastewaters, leaving contaminants in the effluents.
Therefore, the EID should include discussions of the expected levels of remaining products and
contaminants after treatment processes, and plans for handling, treatment and disposal of
residuals. Overall, all proposed pollution control systems should be well-designed,
well-operated, and properly maintained to minimize other impacts.
Petroleum Refining
A variety of impacts may result from technology in use at a typical petroleum refinery.
Impacts, as used here, encompass waste discharges and emissions generated from refinery
processes and operations which enter the environment in air, water, and land, and the resulting
effects caused by their handling .and disposal.
'Many technological and programmatic methods are available to refiners to reduce or
eliminate these impacts. The sections that follow outline the major waste streams (water, air,
and solid waste) and the resulting effluents and emissions, and methods of control.
Raw Materials Extraction, Transport and Storage
The raw materials used by refineries is typically crude oil. Impacts associated with crude
oil exploration, development and production activities are not discussed in this report.
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The crude oil is transported to the refinery by pipeline, tanker or truck. Upon arrival, the
crude is shipped to storage tanks on-site at the refinery, for feed to process systems as needed.
The crude oil is typically a mixture of crude oil, brines and suspended solids. Potential
contaminants of concern include naturally-occurring hydrocarbon compounds, volatile and
semivolatile organics, heavy metals, and nitrogen and sulfur compounds.
The volumes in transit create a potential for large spills in an emergency situation or
accident. Small spills may also occur from equipment leakage, maintenance, or cleaning.
Because of the location of refineries and their associated pipeline or tanker terminals, spills and
leaks can produce discharges of crude oil into local waterways. The major impact of concern
is associated with tanker and truck accidents and the spillage from a major tanker breakup. The,
EID should provide a discussion of the potential occurrence of and impact from tanker accidents
where this mode of transportation is proposed to service the refinery facility.
Gaseous Wastes
Sources of air emissions and pollutants differ considerably among refineries and are a
function of the size of the refinery, the type of crude oil feedstock, the product mix (which
dictates the type and complexity of processes employed), and emissions or pollution control
measures used.
In general, waste gases are emitted from exhaust stacks of fired equipment, tanks and
vessels, flares, open ponds or pits, and equipment leaks (termed fugitive emissions). Additional
intermittent sources result from maintenance activities such as shutdown and cleanout of
equipment and process equipment safety valves.
The waste gases include numerous combinations of components, depending on the source.
The components of concern that may cause environmental impacts are sulfur oxides (SOx),
nitrogen oxides (NOJ, carbon monoxide (CO), hydrocarbons (HC), and particulates. SOx and
NO, are precursors for acid deposition, while NOX and HC are the precursors to the formation
of tropospheric ozone. Both ozone and acid deposition are secondary pollutant problems
resulting from primary emissions of a different pollutant. Other airborne emissions which are
of interest due to their potential for impact are toxic and carcinogenic contaminants such as
asbestos, benzene, and mercury.
The EID should identify, describe (quantitatively), and evaluate all such refinery air
emissions. Interim heat releases, start-up, shut-down, safety valve releases, leaks and any other
potential sources of emissions should be documented in the EID.
Stack Emissions
The acid gases — for refineries, primarily hydrogen sulfide and sulfur dioxide — are emitted
from exhaust stacks, sulfuric acid concentrators, liquid sulfur dioxide refining units, and sulfuric
acid treating units. Hydrogen sulfide may also occur naturally in the crude oil feedstock.
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Carbon monoxide is largely confined to flue gases from catalytic cracking regenerators and
fluid cokers (unless coal or coke are used as fuel for refinery power plants).
Paniculate emissions are generated from cokers, regenerators, and dust sources on-site.
Construction and the local environment (a dry and dusty climate) may also add to the volume
of air-borne particulates.
Nitrogen oxides are formed as a byproduct of combustion, so the main source of NO, is
from the exhaust stacks of fired equipment.
Fugitive Emissions
\
Fugitive emissions are essentially the gaseous leaks from refinery equipment that are not
intended. Air permit regulations require fugitive emissions to be quantified, and some state
requirements include quantifying all piping flanges and connections to estimate the total volume
of contaminants released.
In the BID, the refiner should acknowledge the existence of fugitive emissions and present
emission prevention measures to reduce impacts.
Air Quality Modeling
To facilitate attainment of regional and national pollution standards, it is common for
industry and government to use computer and mathematical simulation to predict the migration
and concentrations of pollutants in air. Air quality models of varying complexity and
applicability are now available. The model or models appropriate for a particular task depend
on many factors, including the accuracy and level of detail desired, the nature of available data,
the capabilities of the modeling technicians, the resources available, and site-specific factors such
as weather pattern characteristics. This next section outlines the basic types of air quality
models preferred by EPA.
There are four basic types of air quality models: Gaussian, numerical, statistical or
empirical, and physical. Gaussian models are the most commonly used steady state models
(models that predict ambient pollutant concentrations at "equilibrium," not as they vary over
time) since they do not require large amounts of data. Numerical models or time-varying
models are often better suited to situations involving more reactive pollutants, but their large
data requirements are often prohibitive. Statistical or empirical models are more appropriate
when the data or knowledge of the relevant chemical and physical processes are inadequate for
Gaussian or numerical techniques.
Physical modeling processes typically involve use of wind tunnels or other sophisticated
equipment. While use of these complex models usually requires expensive equipment and
technical expertise, they may be the best choice for complicated flow situations such as
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downwash conditions, diffusion in complex terrain, or plume effects on elevated terrain.
Physical models are particularly suited to modeling sources in small geographic areas.
Most air models are designed to simulate impacts in two types of terrain: simple or
complex. Simple terrain is terrain where land features are all below the height of the source
stacks. Complex terrain has features that are higher than stacks.
Air models evaluate emissions from a number of source-types:
• Point sources, discrete single sources with known emissions..
• Line sources, used on roads and other linear sources, usually model mobile source
emissions.
• Area sources, assumed when the emissions source is an uncovered lagoon, storage pile,
slag dump, or other source with fairly uniform emissions over its entire surface.
• Volume sources, assumed when modeling fugitive emissions from structures with multiple
exhaust vents or other sources characterized by multiple release points that have different
individual emission rates.
Predicting concentrations at locations that fall between stack height and the height of
maximum plume rise is more problematic. Modeling strategies for these cases are sometimes
dealt with by comparing the hourly concentration estimates from simple terrain models and
complex terrain models, and using the higher values. This technique often entails "chopping
off any terrain lying above stack height for the simple terrain models.
In addition to the terrain-specific design of many models, models generally come in two tiers
of complexity:
(1) screening level models that use worst-case meteorological data to identify sources that
may threaten air quality, and
(2) more advanced models'that use actual meteorological data to give detailed descriptions
of chemical and physical processes.
Screening models give "quick and dirty" estimates that are good enough to identify situations
where air quality standards are not threatened. If these models predict that standards are likely
to be exceeded, however, more detailed and expensive models need to be applied.
The models discussed below deal mainly with selected screening models preferred by EPA.
The Urban Airshed Model (UAM) is the only refined analytical technique described here.
Petroleum refineries are a significant source of VOCs, and UAM is considered by many to be
the only model adequate for modeling VOC emissions from very large, disperse sources such
as petroleum refineries.
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EPA-Preferred Models
Based on factors such as past performance, cost, and availability, EPA recommends certain
models for particular, applications. Recommended screening models for simple terrain are
described below, followed by screening models for complex terrain and the Urban Airshed
Model. All of these models simulate pollutant transport in areas with less than a 50-mile radius.
«
Estimates of emissions can be obtained using emission factors published in EPA (1993b),
or related information that is available from the CHIEFS bulletin board on EPA's Technology
Transfer Network in Research Triangle Park, North Carolina (Telephone (919) 941-5384 or
Internet, through Telnet to ttnbbs.rtpnc.epa.gov).
Simple Terrain Models
Climatological Dispersion Model (COM 2.0)
The CDM is a Gaussian plume model designed to calculate long-term average pollutant
concentrations (on either a seasonal or annual basis) at ground-level in urban areas. It may be
applied in a variety of situations, including point and area sources, flat terrain, migration
distances less than 50 kilometers, and averages over a period longer than one month.
Industrial Source Complex (ISC)
The ISC is a Gaussian plume model that is used to calculate pollutant concentrations from
an array of sources associated with a complex industrial source. The model is designed to
account for the following: downwash; settling and dry deposition of particulates; area, line and
volume sources; separation of point sources; plume rise based on downwind distance; and
limited terrain adjustment. It may be applied to industrial source complexes, rural or urban
areas, flat or rolling terrain, and averaging times from one hour to one year.
Predictions of concentrations for area source emissions by ISC become more accurate the
farther away the site is from the source (up to 50 km).
Multiple Point Gaussian Dispersion Algorithm with Terrain Adjustment (MPTER)
MPTER is a multiple point source model that can be used for predicting the concentrations
of relatively non-reactive pollutants. MPTER may be used to model point sources, rural or
urban areas, flat or rolling terrain that does not exceed stack height, and averaging times from
one hour to one year. MPTER does not model area or volume sources as well as it models
point sources.
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Single Source Model (CRSTER)
CRSTER is another Gaussian plume dispersion program intended to estimate pollutant
concentrations from point sources at a single location. It calculates the highest and second-
highest concentrations for each receiving site over 1-hour, three-hour, 24-hour and annual
averaging times. CRSTER is a suitable model for use with single point sources in either rural
or urban areas.
Models for Complex Terrain
There are currently a number of complex terrain models sanctioned by EPA for regulatory
use. Four of the more commonly used models are discussed briefly below.
Valley Model
The Valley Model is a slightly older (1977), steady-state, Gaussian univariate dispersion
model appropriate for simulating plume impaction in either rural or urban settings for up to SO
point and/or area sources. It estimates concentrations at receptor sites designated by the
program on a radial grid of variable scale. The algorithm used adjusts plume elevations
according to stability class and height of the terrain impacted, and allows for limited mixing.
It is recommended only for 24-hour averaging times, but can estimate annual concentrations as
well.
COMPLEX I
COMPLEX I is a Gaussian dispersion model suitable for simulating multiple sources in rural
areas. It is essentially a modified version of the MPTER simple terrain model, altered by
incorporating a plume impaction algorithm. The model accepts hourly meteorological data as
input, and can be used over all averaging times. Receptor sites may be placed on either a radial
or cubic grid of variable scale. Because it is versatile and easy to use, COMPLEX I is often
the model of choice for complex terrain in rural areas.
CTSCREEN
CTSCREEN is a screening version of the more refined Complex Terrain Dispersion Model
(CTDM). One of its main features is it divides the mixing zone into several layers, as opposed
to the other screening models listed here, which assume uniform mixing up to the top of the
mixing zone. It may be used either in place of the Valley or COMPLEX I models, or as a tool
to further investigate suspected problem areas. Some disadvantages of CTSCREEN are that it
can require significant amounts of digitized terrain data to run, and it can simulate plume
interaction with only one hill at a time.
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SHORTZ and LONGZ
SHORTZ and LONGZ are the models of choice for complex terrain in urban areas. They
may, however, be applied to flat terrain and rural areas. SHORTZ combines.a steady-state
bivariate Gaussian plume algorithm with sequential short-term (usually hourly) meteorological
inputs to calculate average ground-level pollutant concentrations for averaging times from 1 hour
to 1 year. It can simulate emissions from stacks, buildings, or area sources for up to 300
sources. LONGZ is a similar model, but differs from SHORTZ by employing a univariate
Gaussian plume technique with statistical wind summaries to calculate long-term (seasonal and/or
annual) concentrations from up to 14,000 sources.
Urban Airshed Model (UAM)
UAM is a three-dimensional urban scale numerical simulation model designed for use on
entire airsheds. It is designed for calculating ozone concentrations formed under pulsed, short-
term conditions (lasting 1-2 days) as a result of emissions of nitrogen oxides, carbon monoxide,
and volatile organic compounds. As with CTSCREEN, UAM divides the mixing zone into
several layers. It is suitable for urban areas with significant non-attainment for ozone, and
hourly averaging times. As with other numerical models, it is very data intensive, making it
unsuitable when data are not available, and potentially expensive when they are.
Waste Control and Residuals Disposal
To comply with air regulations and permit conditions, the refiner must employ air treatment
systems, pollution control devices and reduction techniques to meet emission standards. The
EID should contain a discussion of the type of control systems and anticipated resulting
emissions levels.
Hydrocarbon emissions can be limited through the use of:
• Floating roofs on tanks;
• Manifolding purge lines to a recovery system (condenser or carbon absorber) or to a
flare;
• Vapor recovery systems on loading facilities;
• Preventive maintenance;
• Enclosed waste treatment plant;
• Mechanical seals on compressors and pumps; and
• Personnel training.
Particulates can be controlled with the use of:
• Wet scrubbers;
• High-efficiency mechanical collectors (cyclones, bag houses); — electrostatic precipitators
on catalyst regenerators and power plant stacks;
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• Controlled combustion to reduce smoke;
• Controlled stack and flame temperatures; and
• Improved burner and incinerator design.
Carbon monoxide emissions can be controlled at the catalytic cracker and fluid coker units
with a CO boiler and at other sites through proper furnace and burner design.
Sulfur dioxide emissions can be controlled primarily through:
• The burning of low-sulfur fuels in furnaces and boilers,
• The wet scrubbing of high-sulfur dioxide flue gases, and
• The removal of sulfur in fuels before use.
Nitrogen oxide emissions can be controlled through:
• An improved combustion process (i.e., lower flame temperature, less excess air)
• Use of low-nitrogen fuel.
Uguid Wastes
Refineries generate substantial volumes of wastewater. Typically, refinery facilities include
extensive wastewater treatment systems on-site, where wastewaters are treated prior to discharge
to natural waterways or to Publicly-Owned Treatment Works (POTWs). These wastewaters may
contain high concentrations of oils and dissolved organics that are not readily biodegradable.
They may also contain chemicals from processes, treatment, or maintenance that can pose
environmental problems.
Refineries may have multiple wastewater collection and treatment systems, for cost effective
design, operation and maintenance, such as process drains, stormwater collection systems, and
sanitary sewers.
The BID should discuss the following:
All wastewater streams (sources, quantities, flowrates, and compositions)
Proposed wastewater treatment systems (capacities and processes)
Effluent discharge stream (quantities, flowrates, and compositions)
Potential hazardous or toxic chemicals in wastestreams
Receiving waters quality and their use patterns.
Aquatic Discharges
Fluid or liquid wastewater streams that are typically generated at a refinery are briefly
described below. The wastewater streams are typically treated on-site prior to discharging to
a waterbody, where appropriate. This type of discharge is controlled through a NPDES permit.
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The NPDES permit will have limits for numerous effluent constituents, such as BOD,,
hydrocarbons, metals, and acids. Wastewater treatment systems can be designed to remove the
offensive constituents to proper levels, as evidenced by existing refinery operations.
Process Wastes
Liquid or fluid waste streams may be generated by processes or maintenance operations.
The EID should describe each of the wastewater streams,' its source and its destination.
Free oil originates from numerous sources such as individual sampling taps, pump gland
leaks, valve and pipeline leaks, losses and spills at times of unit shutdown and equipment repair,
accidental spills and overflows, tank bottom drawoff, and other miscellaneous sources. Some
of the oil mixes with other fluids and becomes emulsified, making it more difficult to treat.
Condensate waters originate from distillate separators, running tanks and barometric
condensers. These waters can contain a variety of chemicals such as sulfur-containing
inorganics, acids, alkalis, suspended solids, and condensed organics.
Acid wastes arise from the catalytic use of various acids and from the acid treatment of
gasoline, white oils, lubricating oils, and waxes. They occur as rinse waters, scrubber
discharges, spent catalyst sludges, condensate, and miscellaneous discharges resulting from
sampling procedures, leaks, spills, and shutdowns. Caustic wastes arise from caustic washing
and may include sulfur and organic compounds. Alkaline waters also occur from washings.
Special solvents and numerous chemicals used in refining operations may be leaked or
spilled and gathered into wastewater streams.
The highest wastewater volume is typically from cooling system blowdown, which can
become contaminated with oil, chromates, biocides, and other chemicals used in cooling towers.
The sanitary wastewater stream can be easily treated on site in a separate treatment system,
or can be sent to the local Publicly-Owned Treatment Works (POTW).
A wide variety of fluid sludges are generated from reactors, storage tanks, wastewater
treatment and process equipment. These sludges may have a low percentage of solids. Sludges
are typically dewatered or filtered to separate solids from the liquids, with the decanted liquids
incorporated into wastestreams for treatment. Sludges may contain organics, sulfur compounds,
and heavy metals.
Stomwater
Stormwater may be a large, yet sporadic, volume depending on the refinery size, location,
and the local climate. The Stormwater effluent may pick up a wide variety of hydrocarbon and
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chemical components from contact with the process and chemical storage areas. Stormwater is
usually collected in a storm water collection or sewer system, and may be sent to the refinery
wastewater treatment system. Contaminant loading problems may occur in wastewater or runoff
discharges if Stormwater is not considered in the refinery design.
New refineries should consider alternatives for managing Stormwater runoff. Recent
Stormwater regulations under the Clean Water Act may impose certain requirements for
monitoring and treatment. The EID should discuss the Stormwater collection and treatment'
system design.
Water Quality Modeling
In this section, five water quality models are discussed. They are all relatively simple to
operate, but the accuracy of their predictions depends largely on the adequacy of data used to
calculate model parameters and characterize externally-driven functions such as water flow. The
discussion of each of these.models is taken primarily from EPA (1993a).
WASP4 (new version WASPS)
WASP4 is a detailed receiving water quality model supported by EPA. It allows users to
interpret and predict water quality responses to natural phenomena and man-made stresses for
various pollution management decisions, particularly for eutrophication (EUTROWASP) and
toxicants (TOXIWASP). It is a dynamic compartment model and includes compartments for the
water column and benthos. The model includes the time-varying processes of advection,
dispersion, point and nonpoint mass loading, and boundary exchanges. It can be run in a one-,
two-, or three-dimensional mode making it applicable to rivers, lakes, estuaries, or open coastal
areas.
UTM-TOX
UTM-TOX was developed by the Oak Ridge National Laboratory for the analysis of
hydrological, atmospheric, and sediment transport of pesticides and toxic substances. This
model uses of a multi-media simulation approach. Given a chemical release to the atmosphere
from a given source, the model uses mass balance formulae to compute chemical movement
from a source, through the atmosphere, onto land, into surface runoff and through the soil, and
finally in sediment and stream flow. The model generates summary tables and plots of average
monthly and annual chemical concentrations in each medium. It also considers biotic processes
and computes chemical accumulation in stems, leaves, and fruits of impacted vegetation.
Application of this model has been limited because of its complexity and lack of user
documentation.
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EXAMS
EXAMS was developed by the EPA to provide rapid assessments of the behavior of
synthetic organics in aquatic systems. Initial versions computed long-term results of continual,
steady discharges of single chemicals into typical aquatic systems. A newer version includes
routines that simulate seasonal variations of discharge, transport, and chemical transformations
and predicts the transport and fate of reactants and products. The model requires extensive data
on the physical properties of discharged chemicals and transformation products and for variables '
describing transport mechanisms and the physicochemical properties of receiving waters.
QUAL2E
QUAL2E is an EPA-supported, one-dimensional model that assumes steady state flow but
allows simulation of diurnal variations in temperature, algal photosynthesis, and algal
respiration. The model simulates a series of nonuniform segments that make up a river and
incorporates the effects of withdrawals, branches, and tributaries. Conservative (non-degrading)
and non-conservative water quality parameters can be handled. It is commonly applied to
temperature, BOD, DO, ammonia, nitrate, nitrite, organic nitrogen, phosphate and organic
phosphorus, and algae. QUAL2E is widely used to determine waste load allocations for
streams.
SMPTOX
SMPTOX is a user-friendly, microcomputer program for screening-level modeling of toxic
discharges to streams and rivers. It also provides a simplified method for allocating discharge
loads for ammonia, chemical oxygen demand, and biological oxygen demand.
Groundwater Contamination
Groundwater contamination is not uncommon under or near existing refineries because of
historical practices and other manufacturing that may have operated nearby. The existing
condition of the local groundwater should be investigated by the refiners. If the desired location
is near a contaminated aquifer, the refiners are faced with another set of concerns, and may face
other requirements set by local agencies.
A new refinery should be designed to prevent groundwater contamination, and may install
monitoring wells to monitor the local groundwater quality. Ideally, a new refinery operation
should not result in groundwater impacts due to proper design and operation. The EID should
contain a statement of the methods of prevention of groundwater contamination, and an
assessment of existing groundwater conditions.
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Groundwater Modeling
The use of air and water quality models is generally straightforward since the medium
receiving, discharges or emissions can be considered to be well mixed, and predictions of
concentrations of pollutants in these are relatively accurate. Such is not the case for most
groundwater models. If is far less simple to model the predicted concentrations of pollutants in
groundwater because of the physical structure imposed by soils and the general lack of detailed
data concerning soil structure and soil-water relationships. Also, the chemical and physical'
nature of soils determines water movement and soil-pollutant-water interactions. The application
of groundwater models is thus more of an art than a science, and considerable expertise is
needed to select appropriate models and apply them appropriately. Nevertheless, there are some
EPA-supported models that can provide some insight into the effects on groundwater of various
waste management practices. These are described below.
PRZM
The Pesticide Root Zone Model is a dynamic compartment model that simulates the vertical
movement of pesticides and other organic chemicals in unsaturated soil within and below the
plant root zone. It is designed to predict movements of pesticides that are applied to soil or to
foliage, and considers pulse loads, the prediction of peak events, and the estimation of time-
varying mass emission or concentration profiles. The model has hydrology and chemical
transport components that simulate runoff, erosion, plant uptake, leaching, decay, foliar wash
off, and volatilization of pesticides. Predictions have a daily, monthly, or annual time frame
(Ambrose and Barnwell 1989).
MULTIMED
MULTIMED simulates movement of contaminants in all media, no matter into which
medium they are first released. In .the groundwater part of the model, the movement of
contaminants is simulated in saturated and unsaturated groundwater zones. MULTIMED uses
a steady-state, one-dimensional, semi-analytical model to simulate flow in the unsaturated zone,
the output of which is used as input to the unsaturated zone transport module. The transport
module simulates transient, vertical transport, including the effects of dispersion, adsorption, and
decay. Outputs from the unsaturated zone modules are used as input to the semi-analytical
saturated zone transport module. The saturated zone transport module incorporates one-
dimensional flow, three-dimensional dispersion, adsorption, decay, and dilution. The model is
not appropriate for heterogeneous soils or interactions between different pollutants, both of
which affect the behavior of contaminants in soil.
3DFEMWATER/3DLEWASTE
The 3DFEMWATER/3DLEWASTE groundwater flow and contaminant transport models
consist of FEMWATER, a three-dimensional, finite element model of water flow through
saturated-unsaturated media, and LEWASTE, a hybrid three-dimensional Lagrangian-Eulerian
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finite element model of waste transport through saturated and unsaturated media. The models
simulate capillarity, infiltration, and recharge/discharge sources (e.g., lakes, reservoirs, and
streams). The models consider steady-state or transient flow conditions in unconfined
homogeneous, heterogeneous, isotropic, or anisotropic aquifers. Processes considered include
advection, dispersion, adsorption, decay, precipitation, and discharging or pumping wells. The
3DLEWASTE model can simulate regional or local groundwater flow systems.
Spills
Spills result in emissions, effluent, and waste to be added to the refinery waste stream. The
impact of spills depends on the location of the spill and the conditions of receiving waterbodies.
The spills of greatest concern are those associated with transportation of large volumes of crude
oil or products across waterbodies, and are discussed above.
Spills may occur during routine operations or maintenance activities. Spills are likely to be
greater when containers or vessels are manually loaded or unloaded than with automatic transfer
operations. Failure of tanks, vessels, or containers occurs infrequently. The refinery design
should incorporate spill containment devices and spill prevention measures, particularly to meet
the Clean Water Act's SPCC requirements.
The EID should contain a discussion of the types of spills that may occur and the response
action planned. The refiner should also include spill prevention measures designed into the
refinery operations and equipment.
Water Control and Residuals Disposal .
Liquid wastes, or wastewater effluent streams are usually routed to an on-site wastewater
treatment plant. The treatment plant design, with the effluent characteristics, flow rates, and
outfalls should be discussed in the EID. The wastewater treatment and effluent discharge may
be regulated by an NPDES permit, POTW requirements, or in some cases, a RCRA permit, or
a combination of the three.
The wastewater treatment system design is dependent on refinery location, refinery plant
size, the refining process (degree of crude finishing), and wastewater characteristics. The EID
should demonstrate that the refiner has given adequate attention to implementation of new
technology for abatement of water pollution. The EID should include an understandable and
complete description of the proposed wastewater treatment system. A process flow diagram also
should be provided to illustrate each step of the treatment scheme. Refineries may use the
following basic treatment processes:
• Removal of free oil and suspended solids by gravity
• Removal of emulsified oil, suspended solids; colloids, and solids by coagulation and
settling, sand filtration, and gas flotation
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• Pretreatment to remove phenols, sulfides, mercaptans, and ammonia and adjust pH (with
processes such as steam stripping, flue gas stripping, oxidation, and neutralization)
• Trickling filters, activated sludge processes, oxidation ponds and aerated lagoons or
biological organisms to convert dissolved organic matter to a settleable floe
• Tertiary treatment to remove dissolved organics and inorganics, color, odor, and taste
(with foam fractionation, activated carbon, ion exchange, electrodialysis, or ultrafiltration)
• Disposal of high organic containing liquids or solids by combustion (incineration)
• Dewatering of sludge arising from biological systems and solids separation processes with
the use of sand beds, vacuum filtration, or centrifugation
• Disposal of sludge by landfill or incineration, or recycling methods.
To determine the optimum wastewater treatment system, there are a number of key factors
which should be considered. The EID should demonstrate the analysis and selection method(s)
used to arrive at the proposed wastewater treatment design. The following information should
be presented:
Systematic consideration and analysis of all alternative wastewater treatment approaches
Constituent loadings from various wastewater streams
System reliability, efficiency, and susceptibility to upset
Energy and material demands of various treatment systems
Excess capacity and expandability of system
BAT for priority and conventional pollutants
Ability to meet receiving water quality standards.
Solid Wastes
Solid wastes generated at refineries include process sludges, spent catalysts, hazardous
wastes, construction debris, and containers. Many solid wastes may contain significant amounts
of leachable heavy metals and organics which could contaminate the environment if not treated
and disposed of properly.
Therefore, to evaluate the potential impacts from solid wastes, the EID should identify all
the solid waste streams. A flow diagram may be provided indicating the generation, collection,
transportation, and disposal of these wastes, and present the following information:
• Source, quantity and chemical composition of solid wastes generated
• Proposed measures to handle and dispose of solid wastes, including descriptions of waste
management units
• Potential environmental impacts and planned mitigation measures
• Composition of leachates from solid wastes.
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Environmental Consequences
Hazardous Wastes
Some wastes generated in refineries are classified as hazardous wastes. The types and
volumes vary with the operations. There are refinery source-specific wastes which are currently
listed hazardous wastes (K048 to K052) (45 FR 74834, S3 FR 46354) because they contain
hazardous constituents such as metals (chromium, copper, nickel, lead, etc.), arsenic, and
organic compounds (benzene, toluene, benz(a)anthracene, benzo(a)pyrene,
dibenz(a,h)anthracene, etc.). These wastes are:
Dissolved air flotation float (K048)
Slop oil emulsion solids (K049)
Heat exchanger bundle cleaning solids (K050)
API oil/water separator sludge (K051)
Leaded tank bottoms (K052)
Primary oil/water separation sludges (F037, F038).
EPA is currently evaluating several more wastes for listing as hazardous.
Additional information on these wastes can be found in API (1993) and EPA (1982).
Other hazardous wastes that may be found are waste chemicals and compounds used in
processes or maintenance activities, which may be RCRA-defmed F, U or P wastes. The RCRA
mixture rule and derived-from rule affect refinery operations as well. In addition, some items
may be hazardous by characteristic or definition, such as certain containers or waste oil.
(Olschewsky and Megna 1/4/88). Oil refineries are not RCRA facilities by definition, but, many
refineries have obtained RCRA permits for wastewater treatment systems that process hazardous
wastewaters.
Hazardous wastes must be managed according to RCRA (or state-equivalent) regulations.
Handling and disposal will be separate from other waste management, and the refiner should
have a hazardous waste management program to ensure compliance.
Other Wastes
Non-hazardous wastes generated at a refinery include solids and sludges. These wastes are
subject to characterization by RCRA requirements, but once determined non-hazardous, may be
managed in a variety of ways. Typically, appropriate waste management techniques are applied
to each stream in the most cost-effective manner.
Spent catalysts are metallic compound wastes generated by the catalytic cracking units. The
volumes are small compared to other waste streams. Catalysts are regenerated in their
respective processes, until capacity is severely limited. Catalysts may be reused in a different
refinery unit, or recycled to a cement kilns for beneficial reuse of the silica component, when
specifications can be met. (Spearman and Zagula 1992)
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Environmental Consequences
Sludges are generated throughout the refinery, resulting from processes and from separation
in tankage. Sludges with a high percentage liquid are usually filtered or separated. The
remaining sludge contains more solids and behaves more like a solid material. The sludge may
be used as a fuel if the BTU value is adequate.
Tank bottom sludges accumulate in tanks from the entrained solids settling out of suspension
to the bottom. The sludges are removed during infrequent tank cleaning. Refiners have
experimented with various methods to minimize the volumes of sludge, .but the acid treatment
of refinery stocks is almost always highly contaminated with metals and other pollutants.
Sludge accumulating at the bottom of cooling towers generally is adaptable to disposal as
fill. However, the removal of the sludge from the tower basin and the transfer of the material
to the point of final disposal can pose numerous problems in cleaning, transportation and storage
because its high density which does not allow it to flow easily, the need to remove liquids from
the sludge, and the need to shut down cooling towers for cleaning. Sludge from water treatment
clarification creates the same type of problems.
Sludge or solids from the water treatment softening process is typically a carbonate
compound. In some cases it may be reused in the refinery for the neutralization of acid waters
or as a coagulant aide in wastewater treatment.
Waste Control and Residuals Disposal
Solid waste volumes and characteristics may be controlled through various measures to
concentrate or eliminate the wastes. Refineries have incorporated waste management and waste
minimization practices to reduce impacts, process and operational inefficiencies, costs, and
future liabilities. These practices are determined on a case-by-case basis.
i
Wastes may be recycled or reused, particularly when there is inherent value in recycling or
reuse. Oily wastes and sludges are typically treated and filtered to recover the oil. The residual
solids are then disposed of.
All wastes must be ultimately disposed of, if not reused or recycled. The following are brief
descriptions of the disposal options that may be used on site or provided by commercial
facilities. The EID should cover the selection of disposal methods to be implemented on site.
The chosen method of disposal for each waste depends on a number of factors, including
the volume generated, the economics of material recovery, the disposal capacity available, and
disposal costs. Waste disposal options also vary with geographic areas and the current market
for wastes.
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Environmental Consequences
Landfills
Landfilling has been the most widely used method for disposing of all types of petroleum
refinery wastes. The environmental impact of landfilling is contingent not only upon the types
and characteristics of generated wastes, but also upon methods of operation and on specific site
geologic and climatologic conditions. Landfills are suited to disposal of de-watered solids and
sludge from non-hazardous process wastes, construction debris, and trash.
Landfills must meet many regulatory requirements (RCRA or state-equivalent and local) that
include proper design and operation, tracking and characterization of wastes, leachate collection
and treatment, environmental monitoring and secure closure. Landfills are required to be
permitted, so much of the technical data will be provided by the refiner during the permit
process. In addition to technical aspects of landfilling, regulatory parameters limit the disposal
of organic-containing sludges and residues in landfills by the land disposal regulations (see
regulatory section).
A refinery proposing an on-site landfill must meet many criteria for design and operation:
• Selection of a site that is geologically sound, of adequate size to provide substantial
capacity, and results in minima] environmental impact
• The routing of surface waters around the landfill site and sloping of cover soil to avoid
on-site runoff and erosion
• Characterization and segregation of wastes to prevent mixing of incompatible compounds,
such as mixing solids containing heavy metals with acids, or solutions with other wastes
which together produce explosions, heat, or noxious gases
• Blending of liquid or semi-liquid wastes with soil or refuse materials to absorb moisture
and reduce fluid mobility
• Neutralization of acid and caustic sludges to minimize reactivity
• Providing daily cover of wastes.
Landspreading has historically been used by many refineries. The land disposal regulations
have limited the applicability of this disposal option. Landspreading is a relatively inexpensive
disposal method, and is typically used for hydrocarbon and organic sludges. Landspreading is
also a treatment method, in that lighter components volatilize and heavier organic components
biodegrade. Landspreading works best in warm, dry climates.
i
Landspreading may cause impacts to the environment, depending on how well the method
is controlled and managed. Potential impacts are oil contamination of ground and surface
waters, accumulation of heavy metals in the underlying soils, and incomplete reduction of
organic acids resulting in the generation of intermediate byproducts.
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Environmental Consequences
The use of lagoons, ponds, sumps and open pits was a standard liquid and semi-solid waste
disposal method for the petroleum refining industry for many years. This method is being
phased out for a variety of reasons, including more stringent regulatory requirements addressing
groundwater contamination, migratory bird endangerment, and air emissions.
The lagoons, ponds, sumps, and open pits are being replaced with enclosed units such as
clarifiers and above- or below-ground tanks. Open pits may still be used for emergency
diversion, temporary treatment basins, or evaporation ponds. Ponds or pits may be required to
be constructed with liners, leak detection and netting to prevent impacts.
Incineration is a method of disposal of semi-solid and solid organic-containing wastes
generated at the refinery. An incinerator must be permitted by regulatory agencies in
conformance with the Clean Air Act. The design and operation must meet the regulatory
requirements specified in the regulatory section.
Incineration of refinery wastes requires a special type of system to provide adequate
detention times, stable combustion temperatures, sufficient mixing, and high heat transfer
efficiency. A fluidized bed is one of the few systems that can satisfy all these criteria. A
fluidized bed is an incineration system in which inert material (e.g., sand) is supported over a
grate. Combustion air is blown through the grate and supports the panicles. Waste and
supplemental fuel are injected into the bed, where combustion occurs.
The material to be incinerated can be injected either into the fluidized bed or immediately
above it. Refinery wastes known to be incinerated by such systems include spent caustic
solutions, API separator bottoms, DAF float, biological sludges, and slop oil emulsion solids.
Experience has shown that the reaction is self-sustaining if the thermal content of the total wastes
incinerated exceeds about 29,000 BTU per gallon. Normal range of operating temperature is
from 1,300 to 1,500 °F. Loss of fluidization and plugging of the bed is still a major problem
in the operation of these units. Reduced temperatures cause discharge of unburned organics.
Subsurface or deep well injection is a disposal method that originated with the oil and gas
extraction industry. Deep well disposal must follow the guidelines established by the Safe
Drinking Water Act's Underground Injection Control Program. This program requires injection
well operations to be permitted.
Large volume, non-hazardous liquid waste streams are suited to deep well injection (e.g.,
brines from crude separation). Other wastes that are difficult and expensive to dispose of
otherwise may also be injected. Deep well injection program capital and operating costs can be
considerable.
Recycling
A liquefied-gas solvent extraction process has been used commercially to remove organic
contaminants from refinery sludges. The benefits of the process are that it meets EPA's criteria
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Environmental Consequences
for BOAT, incorporates recycling, and is less expensive than incineration. The solvent is
recovered and recycled to the refinery crude unit, and the non-hazardous solid residue is
dewatered and may be disposed of in a landfill. (Chemical Engineering, July 1989)
Other Impacts
Odors
Odors are generated from most of the process and waste materials found in the refinery.
Odors will be carried as gases, so the pathways will be those from which air emissions are
generated. The impact of offensive odors is of concern where the public may be in contact, near
the refinery fence line or beyond. Some odors have an offensive characteristic, particularly
those containing sulfur products, such as mercaptans and H2S. The potential odor problem may
be quantified with the air emissions evaluation. Odors may be controlled by air emissions
treatment and control.
Odor controls include a good preventive maintenance program; the treatment of H2S-rich
wastewater streams from the catalytic crackers; gas-processing units and vacuum distillation
towers; and the flaring of H2S, mercaptans, other sulfides, and other odor-producing compounds.
Noise
Refinery operations typically generate elevated noise levels, particularly from equipment
such as compressors, pumps and flares. Construction activities also generate substantial noise
levels. The main impact is on the public, near the refinery fence line.
Because the decibel levels decrease with distance from the noise generation source, refineries
may choose to increase distances from the operations locations to the fence line.
The BID should quantify and evaluate the cumulative noise levels, and include the following:
• Identify all noise-sensitive land uses and activities adjoining the refinery site
• Identify existing noise sources, such as automobile and aircraft traffic and other industry
near the refinery
• Identify all applicable local noise regulations
• Compare projected noise levels with background noise levels
• Assess the noise impact and propose noise abatement measures.
Coal Gasification Impacts
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Environmental Consequences
Coal Extraction
Coal extraction impacts the environment adversely by the alteration of natural habitats, dust
generation, and acid mine drainage. Surface mine sites are generally reclaimed after the
economic life of the mine is over, mitigating the long-term adverse effects on natural habitats.
Dust generation is temporary, and generally not of great significance if attention is paid to its
control. Acid runoff from the mine site, the spoils area, and coal storage area is somewhat more'
problematic. The runoff may have very low pH, and contain suspended and dissolved solids as
well as toxic metals. It is generally very difficult to control because of its diverse sources, and
can persist long after the mine has shut down. Surface mines also have the potential to disrupt
flow of surface and groundwaters.
Regulations under the Clean Water Act require the strict management of mine site runoff
to reduce the impacts of low pH waters and the dissolved and suspended matter, sometimes
toxic, that results.
Transportation
Facilities that use large quantities of coal are found at or very near a coal mine, near a
railroad, or along a large waterway. Using trucks to transport coal over long distances is
generally too expensive to be economically feasible. When coal is transported by trucks from
the mine to the gasifier, the trucks used are not highway vehicles but very large vehicles
specially designed for the movement of coal. They typically run a closed circuit between the
mine and the coal storage pile.
Trains are typically loaded by hopper or conveyor at the mine site, travel over a mine-owned
spur to a main line, and then over the gasifiers' spur to a specially designed storage/conveyor
system where they are emptied (usually through hoppers in car bottoms). Coal is typically
loaded and unloaded from barges or ships by conveyor systems that distribute the coal to storage
piles or directly to process areas.
The impacts from coal transport by trains and barges are through coal loss at loading and
unloading sites, with coal dust generation and spillage along the tracks. Over long periods of
time, the amount of coal lost can be substantial, and problems (acid drainage) similar to those
of coal pile runoff tend to develop along transport routes. The major impact of trucks operating
at a mine site are the fugitive dust emissions from the use of unpaved roads and coal dust
generation and coal loss along the route.
Coal Storage On-SUe
Once received at the gasifier site, coal is placed either on an active coal pile for use within
a week or is placed in an inactive storage pile to be used when the coal supply is interrupted
(weather, mine closings, etc.). The active pile, often on a concrete pad, is normally uncovered
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Environmental Consequences
and monitored visually. Inactive piles are normally not placed on a concrete pad (due to their
large size), but are located, as much as possible, in areas where leaching to groundwater is
minimized. Inactive piles are generally covered with soil, ash, or other impermeable material
to reduce the chance of spontaneous combustion and prevent wetting by rainfall. Some coal
piles are monitored with temperature sensors or gas monitors to warn of pile fires.
Waste Storage and. Disposal
The majority of wastes at a gasifier site are the ash and slag generated during gasification.
These are normally not stored in large quantities at the site. Only about 24 hours' of waste is
stored on-site; it is normally quickly shipped to a landfill or to a recycler. However, some
wastes may be recycled only during specific seasons (in asphalt manufacturing, for example),
and these wastes may be stored long-term on the site. On-site ash storage generates alkaline
(rather than acid) runoff, and since ash tends to be dusty, it is often wetted or covered to
minimize dust generation.
On-site mines are often used as a disposal site since the ash helps neutralize acid drainage,
and it replaces part of the fill material needed to restore the area to the original topography.
Landfills off-site are very common, though again the distance cannot be far to be economical.
All landfill regulations for nonhazardous wastes or these specific wastes must be observed.
Other large quantity wastes will include occasional catalyst changes and cleaning wastes.
These wastes are small in relation to the ash but are large relative to many other sources.
Catalysts that contain valuable metals are recycled. Catalysts made of relatively inert materials
such as zeolites will normally be disposed of in a landfill or recycled if possible. Cleaning
solutions normally require neutralization and filtration prior to discharge to a wastewater
treatment plant. However, the cleaning solutions need to be characterized to determine exactly
how the material can be treated and how it can be disposed of. Most other wastes generated can
be effectively containerized (drums) and disposed of.
Transportation of waste materials may be by train, barge, or by truck. Trucks play a much
greater role in the transportation of wastes than in the transportation of coal. Most ash is moved
by truck as will the spent catalysts. Hazardous wastes will almost always be transported by
truck although some liquid wastes may be sent through the sewer system to a POTW or the
plants own wastewater treatment plant.
Products produced by gasifiers include electricity, synthetic natural gas, and a variety of
gaseous compounds. Byproducts include sulfur, sulfuric acid, or ammonium sulfate. If
electricity is produced, transmission is primarily by above-ground transmission lines. The right-
of-way is kept clear with occasional cutting of the brush and grasses. The impact is to break
up wooded areas and to create areas of increased erosion on steep hillsides. Environmentally
the impacts often are to provide a meadow environment in areas that do not allow such
environments to exist long (eastern woodlands). In western states, where trees are not common,
the only disruption may be to the area immediately surrounding the transmission towers.
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Environmental Consequences
Synthetic natural gas is rarely stored on-site or it is stored in limited quantities in above
ground tanks for on-site usage. Any storage of large volumes is normally done by injection into
natural underground reservoirs that have been emptied. The gas is normally transported by
being pumped into an interstate transmission line, although it may go to a dedicated customer.
The impacts are primarily due to the construction of the pipeline. These are temporary
disturbances of the environment in which the pipeline traverses. The consequences are normally
of short duration in areas that recover rapidly, such as eastern U.S., while desert areas can be
impacted for many years. There are minor air pollution impacts from the compressors.
r
Chemical products such as gases are either pumped directly to the customer or liquified or
compressed and stored in .large above ground storage tanks. Tanks for storage of compressed
or cryogenic gases have very strict construction and maintenance regulations that are followed
due to the hazards associated with this type of storage (note the hazard is primarily to workers
and the plant and, to a lesser extent, the public). The liquified gases may be transported by rail,
truck, or barge while compressed gases are primarily limited to rail transportation
Sulfur can be stored as solid sulfur or as liquid sulfur (if heated). Sulfur storage occurs at
all facilities that produce sulfur. The sulfur as produced may contain as much as 10 % H2S.
The storage of sulfur allows the facility to treat the sulfur with catalysts or by other methods to
remove the H2S so that it may be transported. The storage is in specially designed tanks that
are normally air tight since the H^ is collected and returned to the desulfurization equipment.
After degassing the sulfur may be stored outside as a solid. The solid is normally hard enough
to resist weathering for short periods of time. Liquid sulfur may be shipped by barge, ship, or
train. Very rarely can it be snipped by truck as it is difficult to keep it molten for long. Solid
sulfur can be shipped by any method.
Sulfuric acid is stored on-site in large steel tanks prior to being shipped. The acid is usually
be over 90 % acid (acid below 79 % is more difficult to handle and store). The transportation
of the material may be by any mode, but regulations governing its transport are rigid.
Accidental spills of the material are very bad on a short-term local basis but it can be neutralized
or diluted easily and rapidly. In addition, there is rarely any long-term residual from the spill.
Ammonium sulfate is used as a fertilizer and can be stored and shipped without any special
precautions other than prevention of blowing or spillage. Major effects would be to over
fertilize land or waterways in the event of a spill. This could lead to reduced dissolved oxygen
or algae blooms.
Purification of Crude Gasifier Off-gas
The desired gaseous products of coal gasifiers contain many pollutants that require partial
to nearly complete removal prior to practical use of the gas. Depending on gasifier design and
mode of operation, some or all of the following pollutants are present:
• Particulates (ash and char)
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Environmental Consequences
• Condensable oils, tars and phenols
• Acid gases such as hydrogen sulfide (H2S), carbonyl sulfide (COS), and CO2
• Ammonia (NH3).
Particulate carry-over, when present, includes ash and char, and these are always removed
and generally recycled to the gasifier to prevent down-stream processing problems. Paniculate
carry-over occurs to a greater degree in fluidized bed and entrained flow gasifiers than in
moving bed gasifiers, and there are always paniculate collection devices in use with the former
two types of gasifiers. Cyclones and steel mesh or ceramic filters (for hot gases), or cyclones,
baghouses, and hydroclones (for cooled gases) are used to collect the entrained particulates.
Recycle of char is desirable so that unburned carbon can be more completely converted to a
gaseous product. Recycle of fly ash also results in just one type of ash byproduct rather than
two. When the discharged ash is in the form of slag, this ceramic material is relatively
non-leachable and it is apt to have value as road base or asphalt aggregate.
Condensable oils, tars, and phenols typically are recovered from moving bed gasifiers and
can be handled in several ways. The condensable oils, which are lighter than water, can be used
as fuel oil. Tars, if sufficiently clean can also be used as fuel (tars are distinguished from oils
by virtue of density greater than water). In the Lurgi process, a "dusty tar" that contains ash
is also recovered but this is recycled to the gasifier. Phenols can be recovered and sold as a
byproduct.
Sulfur-based gases are derived from all types of gasifiers that use fuels containing sulfur.
These must be removed for several .reasons. If the sulfur-polluted gases are bumed for power
generation, the sulfur converts to highly undesirable sulfur dioxide (SO]). If the product is to
be used for production of organic chemicals or SNG, the sulfur could interfere with the required
reactions, would possibly poison reaction catalysts, or would result in undesirable impurities in
the desired product.
Although nitrogen occurs to a small extent in coal as organic nitrogen compounds, most of
the nitrogen is released in elemental form in the fluidized bed and entrained flow gasifiers.
However, in moving bed gasifiers, some of the organic nitrogen is convened to ammonia, and
this must be removed at an early stage in the gas purification train in order to avoid down-stream
problems similar to the ones that sulfur compounds may cause. The usual course of actions is
to co-condense ammonia with any oils, tars and phenol, and then separate this mixture in a
side-stream operation.
Methods for Desutfuruation of Coal Gasification Streams
The amount of sulfur in coal varies by type of coal and by mine site, but most coals contain
between 0.5 and 4 % sulfur, and some may have as much as 8.9 % sulfur. The sulfur is usually
present as organic sulfur compounds or as iron pyrite (FeSj), but sulfate salts and elemental
sulfur are also found. The sulfur in coal is easily gasified, but sulfur gasification results in
hydrogen sulfide (H2S) and carbonyl sulfide (COS). These are poisonous, reactive, and
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Environmental Consequences
corrosive gases under most conditions. When burned, H2S and COS result in SO2 and to a
lesser extent SO3.
Sulfur must be removed from the gas stream before being emitted to the atmosphere. If the
gases are to be used for the production of chemicals or pipeline quality gas, the sulfur
'compounds must also be removed.
The biggest problem with removing sulfur for the combined cycle coal gasification power
plants is that most of the more efficient processes require that the gases be cooled to a relatively
low temperature (less than 400 °F) and to near atmospheric pressure. While the energy lost in
cooling can be recovered using heat recovery equipment, the system as a whole loses energy
efficiency.
There are a large number of processes that are used or have been developed to remove
sulfur compounds from gas streams. The majority of these also remove COj. The removal of
COj is necessary for any chemical usage or pipeline quality gas. For on-site combustion for
power, partial CO2 removal is needed only if the concentrations are high. All sulfur removal
processes require that the paniculate matter be reduced to an acceptable level first.
Only a limited number of processes are discussed below. Those discussed generally
represent a type of process; other processes vary in details, but not the overall nature of the
treatment process.
The majority of processes occur in two steps:.the first step removes the acid gases from the
gasifier stream and the second step regenerates and recycles the absorbent material. There are
five major types of processes used: absorption by a solvent, hot carbonate process, physical
solvents, hybrid solvents, and direct chemical conversion. The majority of processes use a basic
solution of alkanolamines (chemicals with both an alcohol and amine group) to absorb the acid
gases. The amine groups react with the chemicals to be removed and the reaction is easily
reversible. The solutions that use alkanolamines have the ability to remove CO2 also since
carbon dioxide rapidly forms carbamates with primary and secondary amines. Almost all other
methods also use basic solutions which react with the H2S to form the hydrosulfide ion HS*1.
Processes that operate at high pressures also have the capability to remove CO^ due to its high
partial pressure.
A category of "dry bed" processes have been or are being developed to remove sulfur.
They are designed to operate in or close to the gasifier's operating conditions and do not require
significant cooling or reduction in pressure. These technologies have the potential to greatly
increase the overall efficiency of the gasifier when used for electrical production since their use
results in less energy loss. Some of these methods use harmless materials in the process
(dolomite, iron oxides). Table 3 lists the most commonly used chemicals and some of their
properties.
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Environmental Consequences
Most processes (see Table 4) remove H2S from the gasifier stream and produce a
concentrated HjS stream which is sent to a process that converts it to a suitable form. The Claus
and Stretford processes are those most commonly used. They produce elemental sulfur, sulfuric
acid, and ammonium sulfate. These processes typically recover 90 % of the sulfur. The tail
gas still contains about 10 % of the sulfur, a level that may exceed environmental regulations.
When this occurs, tail gas cleanup is usually accomplished by other processes, such as the
SCOT, which converts (reduces) all sulfur back to the H2S form and recycles this gas stream
back to the upstream conversion process. Using tail gas treatment, sulfur recoveries of 95 to'
99.9 % can be achieved.
Waste products from the units are for the most part very limited. Solvents are normally
recycled, but a small amount vaporizes. Vaporization is minimized by the facility design and
the selection of solvent.
Solid catalysts used normally last 1 to 3 years before replacement. Metallic catalysts can
be recycled. Dolomite and salts that are used are generally non-hazardous and are disposed of
in landfills or sometimes recycled. The primary concern with the spent materials is the presence
of accumulations of trace quantities of chemicals over long periods of time. Chemicals such as
cyanides, arsenic, and lead can accumulate.
Criteria for selection of a particular process is too involved to discuss in this section.
However, there are limitations on concentrations of the various chemicals that enter the units
(Claus needs H£ at 30 % or greater concentration, while Stretford and Unisulf operate at less
than 10 %; MEA is destroyed by HCN), the temperatures and pressures at which a unit
operates, considerations as to what utilities are needed (water, electricity), other environmental
considerations (e.g., arsenic-based units are generally, not used in the U.S. but are found in
Europe). The units selected are chosen to meet all conditions found at the site, meet all
regulations, and also to be as economical as possible.
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Environmental, Consequences
TABLE 5. CHEMICALS USED FOR Aero GAS CLEANUP
Chemical
MEA— monoethanolamine
DEA— diethanolaRuie
TEA— triethanolamine
DIPA"** diisopjopflnolamine
DGA— diglycolamine
MDEA— memyldiethanolammr
SHJXOT^— 4imethylether of
polyethylene glycol
Rectisol— methanol
F^Os
CaCOsMgO
K2C03
*x>
ft*3
_ . . ^ „_
NaHCO3
KH2As03 + KH2As04
SOj
CuSO4 (Cu+2)
Product
H2S
H2S
H2S
H2S
H2S
H2S
H2S
H2S
H2S
S.S02
H2S
H2S
S
S
S
S
S
H2S04
Comments
Removes CO^ Degraded by HCN. C^, COS. CS2
Similar to MEA. not degraded by COS
Used in SCOT process and many hybrid solvents
Operates at high concentrations (tow operating costs)
A good selective solvent, can be used for CO?
removal, tow capital and energy costs
Removes H2S. CO2, HCN. NH3. COS. CS2
Removes H2S. CO2. HCN, NH3. COS. CS2
Removes H2S. CO2, HCN, NH3, COS, CS2
AHm>rt rliMntml Mmmreinn nmrocc
Difficult iff regenerate
Used for CO2 removal
on this
wy ka on VKjyeu Oalta
(Thylox process dates back to 1929)
Basic Oatis reaction
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Environmental Consequences
TABLE 6. Aero GAS CLEANUP TECHNOLOGIES
Acid Gas Removal
Process
Benfield
CataCaib
Rectisol
Selexol
SepasolvMPE
Sulfint
FlexsorbHP
DELSEP
Ix*Cat
GAS/SPEC
ST1
Process Type
TJ**> ju.Hi-n.BijHJL
.
potassium salt
solution
mctbanol
dimethyl ether or
glycol
Uses vcntnn
ff nftHttMJ ufflt tor
_. « '
reduction to S
K+ salt and
i»
oxidized iron
MDEA
Removes
C02. H2S.
COS
C02. H2S.
COS
C02.H2S.
COS.N2
H2S.CO2
H2S
COz
H2S.C02
H2S
J^S.0^
Product
COfrH*
N2
S
COz
S
H2S
Comment
Preferred asaOOj
removal process
Preferred as a (X>2
removal process
Physical solvent
highly selective
physical solvent for
H2S
.... .
physical solvent f/oM
for COS and
all other sulfur
enmtMundo nennt
are released
The hybrid solvent
gives good CO2
WOllill^ bO|«iB*uy
hieh cone. H<9S may
need cleanup
WxC III KM tftf t •IMUWti
»2" •i**'1"*' *qp*mt»
tolSOpsig
Can be used to
remove CO2 from
Licensor
Union Carbide
Eichmeyer&
r\sso^iafffs
LindeAG.Linde
GmbH
Norton Co7 Allied
BASF
AhifJigxi'llgphgft
Integral
Engineering
Exxon
Enstar Engineering
ARI Technologies
Dow
115
-------
Environmental Consequences
Table 6. Acm GAS CLEANUP TECHNOLOGIES (CONTINUED)
Acid Gas Desuifurization
Process
Clans
MCRC sulfur
rccovexy
Strerford
TAKAHAX
Process Type
oa^tial osufla&on/
catalysis
*
vanadium salt
and ADA
NQ + NaHS +
NaHCOs
Removes
H2S. SO2
H2S
H2S
H2S
Product
S
S
S
S
Comment
>30%H2S,can
also be used to
destroy NH3
Uses 3 or more
tfjkftnru. that *artff*_h
roies aunng
imajamntuvt nf
catalyst
H2S less than 10%
Similar to StictiuHd
but sulfur removed
utu umiuin OB
^y«F
Licensor
rfl^tflT ^^fiffiHA^^wiff
Mineral &
^jtQiucai Resource
Co.
British Gas Corp.
Tokyo Gas Corp.
116
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Environmental Consequences
Table 6. Aero GAS CLEANUP TECHNOLOGIES (CONTINUED)
Tail Gas Cleanup
Process
SCOT (Shell Clans
Offgas Treating)
Beavon Sulfur
Removal Process
(BSRP)
BSRP-Sdectox
Qeanair
Sulnen
ffP
Sulfreen
>
TOP Aqua dans
Unisulf
Process Type
Catalytic
conversion ID
H2S.
(DIPA) recycle
back toClaus
VVOGCSS
Fuel gas and
cobalt molybdate
catalyst to reduce
toH2S
Setectrjx catalyst
Similar to
Stretfbrd
binlmlifae
yuiuyaut
and hydro
fienation to
convert to H2S
absorbed with
MDEA
Oaiw rotaltrvnwf
in a alkaline
earth metal salt
of carboxylic arid
Similar |Q ClSUS
Clans reaction in
aqueous phase
Removes
H2S. COS.
SOj
H2S. COS.
SOz
H2S. COS.
SO2
H2S.S02
H2S.SO2
H2S. COS.
CS2.SO2
H2S.S02
H2S. SO2
H2S
Product
H2S
H2S
S
S
H2S
S
S
S
S
Comment
Commonly used
after Glaus, recycles
back to Clans
Has not been
high CO2 tail gases,
uses MDEA
good on lean tail
gases (5%,or less), a
dry process
3 sages one each for
SO2, H2S. and
COS ft CS2
Discharges as low as
10 ppm H2S
«
CS2 and COS are
convened to SO2 in
a furnace, uses NH3
M on flhonfftwfiff
Low temp (260-
300°F); mnuiple
beds with oojoff
cycles
Reacted is sodium
phosphite solution
for<10%H2S,
similar to Stratford
Licensor
Shell
Union Oil
CA.. R.M.
Parsons
Union Oil
CA.. KM.
Parsons
Jf. Pritchard
Co.
Ford, Bacon &
Davis, Union
Carbide
Institut
Francaisdu
Petiole
Lurgi
Gesellshaft
Stauffer
Chemical
Union Oil GL,
Parsons
117
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Environmental Consequences
118
-------
Other Issues
9. OTHER ISSUES
Consultation and Coordination
Each of the many laws, regulations, executive orders, and policies identified in the
Regulatory Overview section of this guidance document should be addressed in the consultation
and coordination section of an EIS. The applicant should provide a record of their activities and
actions under each of the initiatives. The applicant provided environmental setting and
environmental consequences materials should include sufficient data on the environment issues
raised by these laws, regulations, and orders to identify and analyze the potential impacts.
List of Preparers
The guidelines are specific that all parties, whether EPA, consultant, or applicant, that are
preparers of portions of the EIS or background papers or conducted analyses that are included
in these documents should be listed along with their qualifications and designated responsibility
in the documents.
References
All parties preparing background papers or sections of the EIS must document their personal
communications and references cited rigorously using a recognized publishing standard agreed
to and used by all the EIS contributors. The applicant and EPA must be clear on the level of
source documentation. There should be no question on the source of data, kinds of analysis,
quality of field data, etc. that are used and recorded in the EIS.
119
-------
Other Issues
120
-------
References
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