Assessment and Remediation of Petroleum Contaminated Sites

G. Mattney Cole

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9781351465465
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Environmental Science
• Index: Biological Sciences

Federal regulations have required thousands of underground storage tanks (USTs) to be dug up and removed or replaced. The contamination of soil and ground water from leaking USTs has become widespread and has produced an overwhelming number of sites that require remediation.Assessment and Remediation of Petroleum Contaminated Sites presents the broad scope of the remedial process from initial site assessment to closure in an integrated, understandable format. The book guides you effortlessly through regulatory requirements, site assessments and sampling, and remediation methods. RCRA and CERCLA federal regulations are addressed. The chemistry and toxicology of petroleum hydrocarbons in the remediation process are explained, and factors affecting soil remediation are discussed. Environmental assessments, site characterizations, remediation planning, and remediation methods are all covered in detail. The book is an essential guide for environmental consultants, regulatory agency personnel, engineers, and environmental attorneys.

1 Introduction

The Problem

Until quite recently underground petroleum storage tanks were peacefully out of sight and out of mind. Underground petroleum storage tank systems, USTs, have been buried since the early decades of the twentieth century by directive of the National Fire Protection Association and the Uniform Fire Code for reasons of safety. Gasoline is a Class A flammable liquid and aboveground storage was considered an unacceptable hazard.

Not until the mid-1970s did anyone seriously consider the fact that all these buried USTs might be leaking gasoline into the environment. The fact that approximately 85% of all USTs were steel with little or no corrosion protection went unnoticed. By the mid–eighties, enough incidents had been reported that Congress, through amendments to the Resource Conservation and Recovery Act, and the Comprehensive Emergency Response, Compensation and Liability Act, empowered the Environmental Protection Agency (EPA) to set regulations to ensure proper operation of UST systems.

The EPA issued final regulations on September 8, 1988. The document entitled, Technical Standards for Operation of Underground Storage Tank Systems, was published in the Federal Register on September 23, 1988. The regulations consist of a set of requirements for the owners and operators of UST systems. The principal requirements include notification, corrosion protection, leak detection, and spill and overfill prevention. The leak detection regulations were to be phased in over a period of 10 years. USTs are required to be replaced or upgraded to meet these standards in increments, beginning with oldest tanks first. Tanks installed prior to 1965, or those whose age is unknown, must have been in compliance by 1989. Those installed between 1966 and 1969 must have been in compliance by 1990. Those installed between 1970 and 1974 must be in compliance by 1991; between 1975 and 1979 by 1992; and between 1980 and 1988 by 1993 (Cole, 1992).

Most of the compliance deadlines have already passed. By December 1993, all tanks and piping must have leak detection in place or have a design that is exempt. The requirements for spill and overfill prevention and for corrosion protection come due in 1998. The most recent existing tanks, those installed from 1980 to 1988, must replaced or upgraded to be in compliance by 1998. New UST systems, those installed after 1988, must be in compliance at the time of installation.

The regulations specify that compliance will be enforced at the state level. The federal regulations are the minimum standard for the country, but states may be more stringent. Compliance is delegated to an implementing agency at the state level. Most states generally follow the federal regulations, but a few are more stringent.

Leaking Underground Storage Tanks and Remediation

December 1998 is approaching rapidly. As a result, thousands of buried USTs have been dug up and removed or replaced over the past few years. Estimates vary, but something in the neighborhood of one–third to one–half of all UST systems that have been exposed are associated with moderate to severe contamination. Virtually all existing USTs, those installed prior to 1988, have contamination at least in the backfill due to overfills.

The sheer number of petroleum contaminated sites is staggering. The list of sites on the National Priorities List, the so–called Superfund list, runs to a few thousand sites; the list of registered USTs in the U.S. runs into the millions. The location of petroleum contaminated sites also presents problems. Frequently the contamination arises from the corner gas station near commercial and residential areas. The contaminant plume migrates offsite to pose problems both for remediation and nearby residents.

In a recent report to the House Appropriations Committee, the Office of Underground Storage Tanks (OUST) of the U.S. EPA noted that there are about 1.6 million USTs and 37,000 hazardous substances tanks as of 1992. The EPA estimates that about 20% of the 1.6 million USTs are leaking, and approximately 1,000 confirmed new releases are reported each week. States and responsible parties (RPs) are initiating cleanups at a rate of about 36,000 sites per year and completing about 16,000 sites annually. (Guide, 1993)

Remediation costs vary depending on the complexity of the site. On average, cleaning up contaminated soil costs between $10,000 and $125,000, but can run higher. Groundwater cleanups average between $100,000 and $1 million. According to EPA estimates, costs of remediation are expected to rise as states and RPs address more complicated and expensive sites.

Add in all the abandoned USTs, aboveground petroleum storage tank sites, railroad fueling operations, airports, refineries, and production facilities and it should not be surprising that remediation and restoration of petroleum contaminated sites has become a multibillion dollar a year industry in the United States.

Four factors are important in the overall remediation process. The primary goal of remediation of petroleum contaminated sites is the preservation of public health and safety. Equally important is restoration of the environment in compliance with regulatory guidelines. Then there is the necessity of carrying out the remediation in a cost–effective manner to keep the owner/operator of the site in business and out of bankruptcy court. Finally, the remediation must be carried out to protect the owner/operator from future liability.

As the number of petroleum contaminated sites has risen, the complexity and variety of sites have also increased. At the same time, the importance of legally defensible data has increased until this has become the most important consideration in many remediation decisions. A recent report by the Government Accounting Office notes that environmental sampling and data acquisition are notably flawed and inconsistent.

Remediation of petroleum contaminated sites is not as complicated as remediation of a Superfund site. A petroleum site is not as sensitive and not as contested, and not as expensive. However, a petroleum contaminated site requires careful planning, attention to detail, and a very careful eye on the budget. Even though the site may qualify for reimbursement, regulatory agencies will not reimburse frivolous or unnecessary expenses.

All of these factors combine to place new responsibilities and demands on the environmental professional supervising a remediation project. At one time, the supervisor of a remediation project at a petroleum contaminated site needed to be skilled only in excavating. Now, the individual must combine the skills and talents of engineer, lawyer, scientist, and negotiator. He or she must also be aware of the fine line between the needs of the client and the requirements of regulatory agencies.

Scope and Purpose

The purpose of this book is to present the broad scope of the remedial process, from initial site assessment to closure, in an integrated, understandable, and coherent format. The technical aspects of remediation are but one portion of a complex problem. It is shortsighted to begin remediation without adequate planning and forethought.

First, the eventual remediation is more cost effective if the site is approached in a coherent manner rather than piecemeal.

Second, relations with the regulatory agency or agencies are smoother and less expensive if the remediation plan is in the context of a thorough site assessment.

Finally, the potential for future liability exposure is reduced significantly if the consultant has proceeded with “all due diligence.”

A number of very good specialty books on various technical aspects of remediation of petroleum contaminated soils or groundwater exist — including several from Lewis Publishers. However, none approach remediation from the integrated point of view found in this book and none are concerned with liability avoidance. The central feature of the book and of Chapter 8 is the Corrective Action Plan and closure with as little future liability exposure as possible.

The flow of the book is from regulations and legislation through the various assessment levels to remediation and closure in three broad sections. The beginning is a set of basic information on regulatory requirements, petroleum, and soils and groundwater. These chapters establish an essential foundation before proceeding into the applied material. The middle section describes environmental assessments, site assessment, sampling, and evaluation. This section is essentially data gathering, acquiring information. The results of evaluation and interpretation are only as good as the data on which they are based. However, it should be stressed that data are only numbers and not particularly useful without interpretation. Information, which is useful, is data that have been interpreted and evaluated.

The final section is integration and application of the information acquired. Data integration leads to technology selection and application of the appropriate remediation method or methods. Remediation is accompanied by an ongoing process of evaluation and monitoring leading eventually to closure.

Overview of the Book

Remediation of petroleum contaminated sites is a subject almost without limit. Sites can be as simple as a corner service station with little contamination to a refinery contaminated with hundreds of compounds over every square inch of ground. The field has reached the point where it is no longer a matter of digging out to the property line and backfilling the excavation. Addressing a site requires an understanding of regulations, sampling, corrective action plans, reimbursement funds, budgeting, and the needs of owners and operators. The intent of this book is to provide environmental consultants, managers, and owners and operators with the tools needed to follow a remediation through to completion.

Remediation must necessarily begin with the laws and regulations governing all remedial efforts. Popular support for the environment stimulated the United States to become the world leader in efforts to clean up polluted air and waterways.^‡ The results have generally been positive, in spite of the fact that efforts to clean up hazardous waste — Superfund or NPL — sites are mired in litigation. Enforcement of provisions of the Clean Air and Clean Water Acts, for example, have reduced air and water pollution from very large point sources, such as foundaries, petrochemical plants, and refineries. Large intractable problems remain: agricultural runoff and non–point sources of water pollutants, air quality in cities, sulfur dioxide, SO₂, emissions and acid rain, and large amounts of petroleum wastes.

Completely new legislation is unlikely at this time; however, it is equally unlikely that legislation already in place will be repealed or allowed to expire. Although political support for reenactment of RCRA and the Clean Air Act waned through the recession of 1990–92, prospects for eventual passage of these bills are good. At the time of writing the Comprehensive Emergency Response, Compensation and Liability Act, CERCLA, is also being considered for reauthorization. Given the hostility in some sectors to its liability provisions, passage of a reauthorization bill will happen, but it will not be easy.

Chapter 2 presents a summary of federal environmental statutes that affect petroleum contaminated sites and remedial activities either directly through regulation and permitting, or indirectly through liability considerations. The statutes can be divided roughly into the following classifications:

• Environmental policy

• Hazardous materials

• Water quality

• Air quality

• Protection of national resources

In the above list, hazardous materials legislation can be divided approximately into two branches:

• Technical aspects that are included in RCRA;

and

• Legal considerations included in CERCLA.

All the legislation discussed is rarely applicable to a single site, but taken together it defines the climate in which the UST owner/operators and the environmental companies must function. Federal and state regulations must be factored into the assessment/remediation equation at a very early stage.

Remediation of a petroleum contaminated site is a mixture of “good news/bad news.” The good news is that petroleum compounds are relatively straightforward to treat for the following reasons:

• They form a homogeneous class of compounds;

• They are less dense than water;

and

• They have very low solubility in water.

Since contaminants float on water rather than sinking and dissolve in groundwater only slowly, a single technology is often adequate to treat a site. This contrasts with the hazardous wastes sites for which multiple technologies is the norm.

Most petroleum hydrocarbons are not highly toxic with respect to the environment or to human health; heavier hydrocarbons are not harmful to groundwater, but may constitute a fire hazard. Those hydrocarbons that are toxic have low solubility compared to other common solvents such as methyl ethyl ketone or acetone. Under RCRA, products derived from crude petroleum are regulated substances, but not hazardous substances.^‡ All of these features combine to make petroleum contaminated sites generally easier and cheaper to remediate than hazardous waste or mixed waste sites.

The bad news is that even under normal conditions petroleum contamination can be quite hazardous to work around, particularly gasoline. This is due to the more volatile products constituting a fire or explosive hazard. In at least one instance tunneling equipment set off explosions in highly contaminated soils. Fortunately the explosions were small.

Most petroleum compounds are chronic toxic hazards to humans, especially the aromatic compounds routinely found in the most common contaminant, gasoline. The hazards are particularly prevalent for workers routinely exposed to gasoline vapors since gasoline contains substantial percentages of benzene. Workers in this category include those doing tank removals, environmental sampling and remediation, and inspectors.

The good news is that many petroleum products are readily consumed by soil bacteria with the result that a petroleum contaminated site may, in effect, remediate itself; the bad news is that typically a contaminated area is sufficiently deep that the soil bacterial population is too low to be effective.

This mixture of “good news/bad news” is a result of the particular nature of petroleum products — the chemistry is rather simple, but the formulation is often complex. Understanding the chemical nature of the contaminating agents is an important step in assessing the possibilities for remediation. Chapter 3 is an introduction to the physical and chemical properties of petroleum hydrocarbons and some gasoline additives that can complicate the remedial process.

The chapter is not a course in Organic Chemistry; rather, it is an explanation of the special properties of hydrocarbons that make remediation of petroleum contaminated sites different from remediation of sites contaminated with hazardous chemicals. The most common and abundant petroleum product available is gasoline. Not surprisingly,...

Table of contents

• Cover
• Title Page
• Copyright Page
• Dedication
• Table of Contents
• 1 Introduction
• 2 Environmental Legislation and Regulations
• 3 Petroleum Hydrocarbons
• 4 Soils and Subsurface Characteristics
• 5 Environmental Assessments
• 6 Site Assessments
• 7 Environmental Sampling and Laboratory Analysis
• 8 Data Integration and Technology Selection: The Corrective Action Plan
• 9 In Situ Remediation Technologies
• 10 Non-In Situ Soil Treatment Technologies
• References
• Appendix A Petroleum Products
• Appendix B Summary of Federal Regulations
• Appendix C The Unified Soil Classification System
• Appendix D Documents for Environmental Sampling
• Appendix E CERCLA Case Law
• Glossary of Terms
• Index