Southeast Rockford

Source Area 9/10
Feasibility Study And Proposed Plan

Southeast Rockford Groundwater Contamination Superfund Project

June 2001

Rockford, Illinois

Italicized words are discussed in the "Terms" section at the end of the page.

 

Purpose of this fact sheet

This fact sheet describes the feasibility study (alternative remedies) and the proposed plan for Source Area 9/10 of the Southeast RockfordGroundwater Contamination Superfund project. Fact sheets describing the alternatives and proposed plans for the other three major source areas are available from the information sources listed on the back of this fact sheet. A groundwater remedy, focusing on all the project areagroundwater predicted to be affected by contamination in the next 65 years, was chosen in 1995. The groundwater remedy is described below.

What is Source Area 9/10? Source Area 9/10 is an industrial area in southeast Rockford shown on the map below. When the project began, the sources of groundwater contamination in southeast Rockford were unknown. In the Phase I project investigation, the Illinois Environmental Protection Agency (Illinois EPA) identified 14 study areas as possible sources of contamination. After several years of study, the Illinois EPA identified four of these study areas (Areas 4, 7, 9/10 and 11) as the major sources of groundwater contamination in this project. These study areas, therefore, were renamed Source Areas 4, 7, 9/10 and 11.

What are the main contaminants at Source Area 9/10? The contaminants at Area 9/10 are mainly industrial solvents with lesser concentrations of chemicals found in oil and gasoline. Most of the solvents are in a class of chemicals called volatile organic compounds (VOCs). "Organic" means the chemicals contain carbon and "volatile" means they evaporate easily. Almost all the solvents are found beneath ground surface. The enclosed "Remedial Investigation" fact sheet has more information about Area 9/10 contamination.

What is the Source Area 9/10 proposed plan? For each source area, the Illinois EPA and the United States Environmental Protection Agency (U.S.EPA) designated one soil remedy and one leachate remedy as the proposed plan. The agencies studied three alternative soil remedies (Table 1) and five alternative leachate remedies (Table 2) for Area 9/10. Of these alternatives, the agencies propose soil vapor extraction (alternative SCS-9/10C) for the soil and the reactive barrier wall system (alternative SCL-9/10D) for the leachate. The public is invited to comment on all alternatives.

Source area 9 / 10 proposed plan. Soil vapor extraction and reactive barrier wall.
Table 1
SOIL ALTERNATIVES
Source Area 9/10
AlternativeSummary descriptionTime*Cost
SCS-9/10ANo ActionNo action.The longest amount of timeNone
SCS-9/10BLimited ActionInstitutional controls. Institutional controls would be used to restrict use or access to the property until reactive barrier wall are met.Same as SCS-9/10A$28,000

SCS-9/10CSoil Vapor Extraction and Granular Activated Carbon Treatment.

 

A series of soil vapor extraction (SVE) wells
connected by underground piping would be installed in the area above the water table. Since the contaminants are VOCs and therefore volatize easily, the vapor phase of the contaminants collect in the underground air spaces above the water table. A vacuum applied to underground wells and piping would collect the vapors from these air pockets. When they are collected, more vapors from contaminants in the soil and groundwater would move into the air pockets above the water table thus reducing the amount of contaminants in the soil and groundwater.
Granular activated carbon. The vapors collected by the SVE system would be passed through granular activated carbon, which removes contaminants from the vapors before the vapors are released into the air.
Air monitoring. A proof of performance test would be conducted before standard operations, and air emissions would be monitored during standard operations to ensure all air quality standards are met.
Shortest amount of time of Area 9/10 soil remedies$4,308,000
* Length of time to meet remediation goals. Because of incomplete data, the time to meet remediation goals is not discussed in specific time frames but only in relationship of one alternative to another.
The Illinois EPA and U.S.EPA prefer this alternative for the Source Area 9/10 soil remedy.

What is leachate? Leachate is source material that has migrated, or could potentially migrate from a source area intogroundwater in the vicinity of the four primary source areas. For purposes of the Proposed Plan, leachate includes source materials at Areas 4, 7, 9/10, and 11 that are sources of contamination in the groundwater at those areas which must be contained or controlled to protect human health and the environment.

What is the groundwater management zone (GMZ)? The GMZ is the area of contaminated groundwater that will be treated by the area 9/10 leachate remedy. The map above shows the GMZ boundary. The groundwater beyond the GMZ will be treated by natural attenuaton as specified in the groundwater remedy described below.

Why do the Illinois EPA and the U.S.EPA prefer alternatives SCS-9/10C and SCL-9/10D for Area 9/10? Soil vapor extraction and the reactive barrier wall are preferred for the following reasons. (1) SVE substantially reduces risks by treating the contaminants in the soil, thus protecting human health and the groundwater over the long term. (2) The reactive barrier wall will immediately stop migration of contaminants to groundwater beyond the GMZ. (3) The alternatives will comply with all federal and state laws. (4) They reduce toxicity. (5) They are cost effective and implementable.

What is the purpose of the remedy? The remedy has several purposes including:

  • to stop ongoing contamination of the groundwater by Area 9/10 waste, thus protecting the water resource for further generations;
  • to reduce the potential for people to come into direct contact with free product and contaminated soil beneath the ground surfaces;
  • to comply with the 1995 Record of Decision for the project that required groundwater contamination sources be controlled; and
  • to ensure that VOCs in soil gas do not move into basements of nearby buildings.

How are remedies evaluated? The federal Superfund law specifies the following nine criteria for evaluation of remedies. They are: (1) overall protection of human health and the environment, (2) compliance with relevant state and federal law, (3) long-term effectiveness and permanence, (4) reduction of toxicity, mobility or volume of contaminants through treatment, (5) short-term effectiveness, (6) implementability, (7) cost, (8) state acceptance and (9) community acceptance.

Table 2
LEACHATE ALTERNATIVES
Source Area 9/10
AlternativeSummary DescriptionTime*Cost
SCL-9/10A No ActionInstitutional controls. Institutional controls would be used to restrict use or access to the property until remediation goals are met.
Groundwater monitoring. Groundwater would be monitored through a system of six monitoring wells until drinking water standards are met at the GMZ boundary.
The longest time of the five alternatives$217,000
SCL-9/10BGroundwaterMonitoring, LeachateContainment/Collection and Treatment by Air strippingSame as SCL-9/10A plus the following:
Leachate containment. Fifty-five wells and underground piping would be installed to collect leachate.
Air stripping. The contaminants would be removed from the leachate by air stripping.
Discharge of treated water. The treated water would be discharged to an offsite storm water ditch located about 2,000 feet south of Area 9/10.
Granulated activated carbon. The vapors from the air-stripping unit would be passed through granulated activated carbon, which would remove the contaminants before the air is released into the atmosphere.
Air monitoring. A proof of performance test would be conducted before standard operations, and air emissions would be monitored during standard operations to ensure all air quality standards are met.
More quickly than SCL-9/10A but not as quickly as SCL-9/10C$2,440,000
SCL-9/10C Air sparging-Required to Operate in Conjunction with SVE as in SCS-9/10C.Same as alternative SCL-9/10A plus:
Air sparging. A series of air injection wells would be installed downgradient of the GMZboundary. An air-sparging unit would inject air into the contaminated groundwater, causing the contaminants to volatize into the air pockets in the soil above the water table. The air sparging would have to be operated in conjunction with the SVE of SCS-9/10C, because the SVE is needed to collect the underground vapors before they are treated by granulated activated carbon.
Shorter time than SCL-9/10B but not as quickly as SCL9/10E$3,208,000
SCL-9/10D Reactive Barrier Wall

 

Same as alternative SCL-9/10A plus:
reactive barrier wall. This wall would be constructed beneath ground surfacedowngradient of the GMZ boundary. The wall would consist of permeable iron filings. As contaminated groundwater (leachate) flows through the iron, a chemical reaction takes place that breaks the VOCs into harmless compounds.
Groundwaterwould meet goals as soon as wall in place. Soil time would depend on soil remedy$3,523,000
SCL-9/10E EnhancedAir spargingSame as SCL 9/10 C plus:
Additional air sparging wells installed in the most highly contaminated portions of Area 9/10
Short, second only in comparison to SCL-9/10D$3,619,000
* Because of incomplete data, the time to meet remediation goals is not discussed in specific time frames but is discussed only in comparison of one alternative with another.
The Illinois EPA and U.S.EPA propose this alternative for the Source Area 9/10 leachate remedy.

What are the Area 9/10 remediation goals? Remediation goals are cleanup objectives. The remediation goals for Area 9/10 are set primarily for VOCs, because VOCs are found in the groundwater. The remediation goals for soil are based on state guidelines (called the Tiered Approach to Cleanup Objectives or TACO) for residential soil and protection of groundwater. The remediation goals for leachate (Area 9/10 groundwater) are the U.S.EPA drinking water standards at the GMZ boundary. Semi-volatiles (such as chemicals found in oil and asphalt) were also detected in Area 9/10. The Illinois EPA will take more samples to see if they are contaminants of concern or if they are at concentrations that are commonly found in urban environments.

Is my water safe to drink? If you are connected to the Rockford Public Water Supply, your water is safe to drink. The City of Rockford routinely tests its supply for possible contaminants. Water that fails to meet U.S.EPA drinking water standards is not distributed to the public.

Next Steps

How is the final remedy decision made? After the public comment period has ended, the Illinois EPA and U.S.EPA will carefully consider all the oral comments made at the hearing and all written comments received. Based on these considerations, the Illinois EPA and U.S.EPA will make a final decision on the Area 9/10 remedy as well as the remedies for the other three major source areas. The Illinois EPA will notify the public of the final decision in a Record of Decision. The Illinois EPA will also summarize the public comments received and the agencies' responses to these comments in a responsiveness summary.

Who will pay for the remedy? The Illinois EPA and U.S.EPA will enter into negotiations with responsible parties to pay for the remedy. If responsible parties are unable or unwilling to pay for the Area 9/10 remedy, funds will be used from the federal Superfund and the Illinois Hazardous Waste Fund to construct the remedy. The agencies will then seek cost recovery from responsible parties.

When will the remedy be constructed? The Illinois EPA and the U.S.EPA plan to begin designing the remedy this summer or fall and begin construction in late 2001 or early 2002.

The Groundwater Remedy

In 1995, after carefully considering public comment, the Illinois EPA and the U.S.EPA chose a remedy for the area-widegroundwater (groundwater outside the groundwater management zones of the four major source areas). The City of Rockford (with U.S.EPA oversight) began implementing the groundwater remedy in 1998. The groundwater remedy includes the following:

  • Rockford Public Water Supply connection for all properties with private drinking water that are in an area predicted to be affected by the contaminated groundwater within the next 70 years (65 years from present).
  • Continued treatment of Rockford Municipal Well #35 with granular activated carbon.
  • Monitoring of the contaminated groundwater plume and, if necessary, connecting additional properties to the Rockford Public Water Supply, if they are threatened by contamination.
  • Treatment of the groundwater by natural attenuation. Natural attenuation is a process by which contaminants are broken down by naturally occurring microbes in the soil or by other natural processes.
  • Control of the four major source areas. This fact sheet describes possible remedies and the proposed plan to control source Area 9/10. Fact sheets describing proposed remedies for the other three source areas can be obtained from Illinois EPA staff or other sources listed at the end of this fact sheet.

Terms

Air stripping.
A method of removing volatile chemicals (chemicals that vaporize easily) 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 (chemicals that vaporize easily) 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.
A method of treating volatile organic compound (VOC) vapors so they are broken down into harmless chemicals. See fact sheets on treatment units for more information on catalytic oxidation.
Downgradient.
The direction groundwater flows. Water flows "downhill" or downgradient.
Free product.
Chemicals present in high enough concentrations that they are undissolved in water. See NAPL.
Groundwater.
Water beneath the ground surface.
GMZ (groundwater management zone).
An area of contaminated groundwater that will be treated by the Area 4 leachate remedy. The goal of the Area 4 leachate remedy will be met when groundwater at the GMZ boundary meets federal drinking water standards. The groundwater outside the GMZ will be treated by natural attenuation as described in "The groundwater Remedy" above. The map on above shows the boundary of the GMZ for Area 4.
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.
Source material that has migrated, or could potentially migrate from a source area into groundwater in the vicinity of the four primary source areas. For purposes of the Proposed Plan, leachate includes source materials at Areas 4, 7, 9/10, and 11 that are sources of contamination in the groundwater at those areas which must be contained or controlled to protect human health and the environment.
LTTD (low temperature thermal desorption).
A unit that heats soil to a point where volatile organic compounds such as found in Area 4 will vaporize (evaporate). Vapors would be treated before being released to the atmosphere. See fact sheet on treatment units for more information on low temperature thermal desorption.
NAPL (non-aqueous phase liquid).
Free product. When a contaminant is present in high enough concentrations in groundwater, it does not dissolve in the water. Rather, if it 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.
Natural attenuation.
A natural process. Either naturally occurring microbes in the soil break down the contaminants into harmless components or the contaminants become adsorbed (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.
Reactive barrier wall.
An underground trench filled with a reactive substance such as iron filings. As groundwater moves through the wall, contaminants such as VOCs react with the iron to form non-toxic compounds. During the wall construction, two jetting wells would be installed within the iron filings. These wells would allow for rejuvenation (renewal) of the iron media by flushing out solids or biological growth that could clog the reactive wall.
Remediation goals.
Cleanup objectives. Remediation goals determine the amount of contamination that must be removed before the remedy is considered complete. For example, the leachate remediation goal at the groundwater management zone boundary for the chemical 1,1,1-trichloroethane is 200 parts per billion. (Two hundred parts per billion is the federal drinking water standard.) The remedy for leachate will not be considered complete until the groundwater is cleaned to the point where no more than 200 parts per billion 1,1,1-trichloroethane remain at the GMZ boundary.
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.
SVE (soil vapor extraction).
A method of removing volatile organic compounds 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 VOCs 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.
Superfund.
The common name given to sites on the National Priorities List (NPL). The NPL is a list of the nation's most serious hazardous waste sites that are eligible for investigation and, if necessary, a remedy under the federal Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), sometimes called the Superfund law. The Southeast Rockford groundwater Contamination project was placed on the NPL in 1989.
U.S.EPA.
The United States Environmental Protection Agency.
VOCs (volatile organic compounds).
Volatile means the compounds vaporize (evaporate) readily under normal conditions. The compounds are called organic because they contain carbon.

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:

Tammy Mitchell
Community Relations Coord.
Illinois EPA
1021 N. Grand Ave. E.
Box 19276
Springfield, Illinois 62794-9276
Phone: (217) 524-2292
Thomas Williams
Project Manager
Illinois EPA
1021 N. Grand Ave. E.
Box 19276
Springfield, Illinois 62794-9276
Phone: (815) 223-1714

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

Rock River Branch
Rockford Public Library
3128 S. 11th Street
Rockford, IL 61109
815-398-7514
(Call for hours)
Ken-Rock Community Center
3218 S. 11th Street
Rockford, IL 61109
815-398-8864
(Call for hours)

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.