Southeast Rockford Groundwater Contamination Superfund Project

Fact Sheet

Record of Decision

Southeast Rockford Groundwater Contamination Superfund Site

Source Control Remedies

May 2002

Rockford, Illinois

Background.

From June 11, 2001 through August 20, 2001, the Illinois Environmental Protection Agency (Illinois EPA) held a public comment period on the feasibility study and proposed plan for control of the four major sources of groundwater contamination in the Southeast Rockford Groundwater Contamination Superfund Project. (See the map on page 3.) The Illinois EPA held a public hearing on July 19, 2001, to receive oral comments on these proposed remedies. After carefully considering all written and oral comments, the Illinois EPA and the U. S. Environmental Protection Agency (U.S.EPA) have issued a Record of Decision for a soil remedy and a leachate remedy for each of the four areas. All remedies are the same as proposed in the proposed plan, with the exception of the Area 9/10 leachate remedy. A summary of these remedies follows.

Summary of Chosen Remedies

Source Area 4

Soil Remedy. Institutional controls plus soil excavation and on-site treatment of soils by low temperature thermal desorption (LTTD).

Leachate Remedy. Institutional controls plus leachate containment and treatment.

Source Area 7

Soil Remedy. Institutional controls plus soil vapor extraction and air sparging.

Leachate Remedy. Institutional controls plus multi-phase extraction, leachate containment, air stripping and treatment of vapors by catalytic oxidation.

Source Area 9/10

Soil Remedy. Soil vapor extraction and treatment of vapors by granular activated carbon.

Leachate Remedy. Institutional controls plus enhanced air sparging. There is a contingent remedy of pumping and treating the groundwater/leachate if the results of further investigation of Area 9/10 indicate such a contingent is necessary.

Source Area 11

Soil Remedy. Institutional controls plus soil vapor extraction and treatment of vapors by catalytic oxidation.

Leachate Remedy. No Action (Institutional controls).

Terms used in the remedies are defined below.

Next Steps

When will construction begin? The Illinois EPA will begin design of the Area 4, 7 and 11 remedies immediately. The plan is to begin actual construction in 2003. For Area 9/10, the State of Illinois and the U.S.EPA are entering into negotiations with potentially responsible parties (PRPs) to conduct additional investigations needed for the design and implementation of the remedy in Area 9/10.

What will happen to Area 9/10 if negotiations with the PRPs are unsuccessful? If negotiations are unsuccessful, the federal Superfund will pay 90% of the cost and the Illinois Hazardous Waste Fund will pay 10%. The Agencies would then seek to recover these costs plus interest from the PRPs.

How will the remedies for Areas 4, 7 and 11 be funded? In a January 13, 1999 amended consent decree, the City of Rockford, with contributions from other parties, agreed to pay a $5 million cash-out for Area 7. The U.S. and Illinois governments gave covenants not to sue for further costs in Area 7 to parties that contributed to the costs the City of Rockford incurred by this settlement. The remedies for Area 4 and 11 will be funded totally by the federal Superfund (90%) and the Illinois Hazardous Waste Fund (10%).

What is the source of money for the federal and state funds? The Illinois Hazardous Waste Fund is generated by several sources including the collection of fees for the disposal of hazardous waste, costs recovered from responsible parties and general appropriations from the State legislature. Until 1995, the source of funds for the federal Superfund was a tax on chemical and petroleum industries. The authorization to collect this tax expired in 1995. Since then, cleanups have been conducted with funds that had been collected before the taxes expired and by general appropriations from Congress. The amount available in the Superfund has been decreasing.

Will funding and reauthorization of the Superfund law have an effect on the Southeast Rockford Project? After the designs for the remedies are complete, the Illinois EPA will apply to the U.S.EPA for 90% of the funds needed to construct the remedies. Funding of this project is subject to the availability of federal dollars.

When will the Illinois EPA conduct the basement air sampling mentioned in the Record of Decision? That work is planned for this fall or winter.

Definitions

Air stripping.

A method of removing volatile organic compounds from water. Often, air stripping consists of letting water fall over a distance in a confined area, exposing the volatile chemicals to air and thus allowing them to evaporate. Usually, the vapors from an air stripping system are collected and treated before being released into the atmosphere.

Air sparging.

A method of removing volatile organic compounds from groundwater. During the process, air is forced into groundwater. Volatile chemicals then vaporize or move into the air bubbles. The air bubbles move with the chemical up to the air pockets in the soil above the groundwater (water table). Usually, air sparging is accompanied by a system, such as soil vapor extraction, where the vapors (with the chemicals) are collected and treated.

Catalytic oxidation unit.

A method of treating volatile organic compound vapors so they are broken down into harmless chemicals.

Free product.

Chemicals present in high enough concentrations that they are undissolved in water. If the free product is lighter than water (like oil), it will float on top of the water. If it is heavier than water, it will sink through the water until it comes to a barrier such as rock or clay.

Groundwater.

Water beneath the ground surface.

GMZ (groundwater management zone).

In this case, a GMZ is an area of contaminated groundwater that will be treated by the leachate remedies. Typically, the goal of a remedy is to meet federal drinking water standards at the GMZ boundary; however, the Illinois EPA will consider background concentrations coming into the Source Areas when setting remediation goals.

Institutional controls.

An administrative or legal constraint that limits land or resource use. Controls could include zoning restrictions, city ordinances, easements, covenants, consent decrees, notices on deeds, or state registries.

Leachate.

Water that has passed through waste and picked up contaminants present in the waste. In this fact sheet, the term leachate refers to all contaminated groundwater within the groundwater management zone boundary.

Leachate containment.

A system in which leachate is collected through a series of extraction wells constructed to prevent the leachate from moving past the GMZ boundary.

Low temperature thermal desorption unit (LTTD).

A unit that heats soil to a point where volatile organic compounds such as found in Area 4 will vaporize (evaporate). In Area 4, excavated soil will be treated on-site in a mobile low temperature thermal treatment unit. The LTTD unit will heat the soil to about 900°F at which point the VOCs volatilize (evaporate) off the soil. The VOC vapors from the soil will be directed to a (1) baghouse where particulates such as dust will be removed, then to an (2) afterburner where vapors will be heated to 1400° to 1800°F. This high temperature breaks the VOC molecules into harmless chemicals such as oxygen and carbon dioxide plus hydrochloric acid. A scrubber will treat the acid to form water and salts. Neutralized water will be discharged to a nearby drainage ditch. After treatment is complete, the unit will be removed.

Multi-phase extraction.

A vacuum applied to a series of extraction wells that collects soil vapors, free-product and groundwater. (Vapors, free product and water are different "phases" thus, the term "multi-phase extraction").

Natural attenuation.

A natural process. Either naturally occurring microbes in the soil break down the contaminants into harmless components or the contaminants become absorbed (attached) to soil particles preventing them from moving into the groundwater. Groundwater beyond the GMZ boundary will be treated by natural attenuation alone and will meet drinking water standards in an estimated 200 years.

Scrubber.

An air pollution control device that removes compounds with a low pH (such as hydrochloric acid) from gas before the gas is released into the atmosphere. Some scrubbers use dry materials such as calcium carbonate while others use water to remove acid gases.

Soil vapor extraction (SVE).

A method of removing volatile organic compounds (VOCs) from contaminated soil and groundwater. Soil vapor refers to the air in spaces between soil particles beneath the ground. These spaces are called soil pores. Since the nature of volatile organic compounds is that they vaporize easily, they will vaporize from contaminated groundwater or soil into the soil pores. In SVE, these vapors are sucked out of the soil pores and usually pumped to the surface. The vapors are directed into a liquid vapor separator. The liquid is collected and sent off-site for proper treatment/disposal. The vapors are usually treated and released into the atmosphere. When the VOC vapors are removed from the soil pores, more VOCs vaporize from the contaminated soil or groundwater into the pores. These vapors, in turn, are extracted by the SVE system thus gradually reducing the amount of VOC contamination in the soil or groundwater.

Volatile organic compounds.

Chemicals that are organic (contain carbon) and that volatilize (evaporate) readily at normal temperatures. The industrial solvents that contaminated southeast Rockford private wells are volatile organic compounds.

For More Information:

Contacts: For more information about the project including fact sheets on the remedial investigation results, feasibility studies and proposed plans for each of the four major source areas, you may contact the Illinois EPA staff listed below:

Repositories: Full reports for the project may be reviewed at the following locations.

Administrative record file: The administrative record file is located at the Illinois EPA headquarters in Springfield, Illinois. Call 217/782-9878 for an appointment. The administrative record file will also be located on microfiche at the Main Branch of the Rockford Public Library at 215 N. Wyman in Rockford.