Fact Sheet 10b
Source Area 7 Feasibility Study and Proposed Plan
Southeast Rockford Groundwater Contamination Superfund Project
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 controlling one of the four major source areas, Source Area 7, of the Southeast Rockford Groundwater 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. Source area control was one part of the overall groundwater remedy chosen in 1995. Other components of the groundwater remedy are described below.
What is Source Area 7
Source Area 7 is a former unregulated disposal area located north and east of Balsam Avenue in southeast Rockford. It now consists of Ekberg Park, fields and open land. (See map below).
When the project began, the sources of groundwater contamination in southeast Rockford were unknown.
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 is the Source Area 7 proposed plan
The Illinois EPA and the U.S. Environmental Protection Agency (U.S. EPA) divided the possible remedies for each source area into remedies for the soil and remedies for the leachate. For Area 7, the agencies studied five possible remedies for soil (Table 1) and three possible remedies for leachate (Table 2.)
Of these remedies, the agencies propose soil vapor extraction and air sparging (Alternative SCS-7E) for soil and multi-phase extraction and leachate containment (alternative SCL-7B) for leachate. The public is invited to comment on all of the alternatives.
What are the main contaminants at Area 7?
The main Area 7 contaminants are industrial solvents containing chlorine. The solvents are in a class of chemicals called volatile organic compounds (VOCs). The chemicals are called "volatile", because they vaporize (evaporate) rapidly and "organic" because they contain carbon.
Analyses of Area 7 soil samples indicate some chemicals may be present in high enough concentrations that they are not dissolved in the groundwater. Chemicals undissolved in water are called non-aqueous phase liquid ( NAPL). Sometimes NAPL is called free product. The enclosed "Remedial Investigation" fact sheet has more information about Area 7 contamination.
What is leachate?
Leachate is 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.
What is the groundwater management zone ( GMZ)?
The GMZ is the area of contaminated groundwater that will be treated by the Area 7 leachate remedy. The map above shows the GMZ boundary. The groundwater beyond the GMZ will be treated by natural attenuation as specified in the groundwater remedy described below.
What is the purpose of the Area 7 remedy
The remedy has several purposes including:
- to stop ongoing contamination of the groundwater by Area 7 waste, thus protecting the water resource for further generations;
- to ensure that VOCs in soil gas do not move into basements of nearby residences; · to protect people from ingestion of produce grown in contaminated soil in the park. See map above.
- to reduce the potential for people to come into direct contact with contaminated soil and free product beneath the ground surfaces; and
- to comply with the 1995 Record of Decision for the project that required groundwater contamination sources be controlled.
How are the 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.
Why do the Illinois EPA and the U.S.EPA prefer alternatives SCS-7E and SCL-7B for Area 7
Soil vapor extraction, air sparging and multi-phase extraction substantially reduce risks by (1) treating the contaminants in the soil, thus protecting human health and the groundwater. (2) These alternatives comply with all federal and state laws. (3) They would remove free product and the contamination from soils contributing to site-wide groundwater contamination. (4) Since the contaminants are destroyed, the solution is permanent and reduces toxicity. (5) The alternatives are cost effective and implementable.
What are the Area 7 remediation goals
Remediation goals are cleanup objectives that must be reached before the remedy will be considered complete. The soil goal is based on State of Illinois guidelines (called the Tiered Approach to Corrective Action Objectives or TACO) for residential soil and protection of groundwater.
The leachate goal is the federal drinking water standards at the GMZ boundary. The groundwater beyond the GMZ boundary is being treated by natural attenuation, which is the remedy chosen for area-wide groundwater in 1995. For more information on the 1995 Groundwater Remedy, see below).
Commonly Asked Health Questions
Is my water safe to drink
Your drinking water is safe, if you are connected to the Rockford Public Water Supply. 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.
Is Pine Manor Subdivision built on an old disposal area
No. Old aerial photographs and Illinois EPA test results confirm that the western boundary of the old disposal area is located several hundred feet east of the Pine Manor Subdivision.
Will vapors from the chemicals in the disposal areas move into my basement
Present information indicates that it will not. The Illinois Department of Public Health (IDPH) and the Illinois EPA tested the basement air in several homes around Area 7 in 1992 and 1993. IDPH concluded that the concentrations detected in basements near Area 7 were below levels of health concern. Since many of these chemicals are found in household products such as paints and glue, the source of detected levels could not be determined. The U.S. EPA and Illinois EPA plan to repeat sampling of several homes near Area 7 during the design phase of the remedy-probably in 2001. These tests will make sure that levels have not increased and will provide data for U.S. EPA to compare to guidelines they are currently using.
Is it safe for children to play in the park
Yes. Illinois EPA samples showed that the major contamination is several feet below the ground surface. Illinois EPA evaluation of surface samples showed no contamination at levels of concern for people using the park.
|SCS-7A No Action||No action.||80-90 years||None|
|SCS-7BLimited Action||Institutional controls. Institutional controls would be placed on the property restricting use and access to the property until remediation goals are met.||80-90 years||$275,000|
|SCS-7C Ex-Situ Biological Treatment|| Soil excavation. An estimated 57,000 cubic yards of soil, waste and free product would be excavated and dewatered. Due to the levels of volatile organic compounds (VOCs), a temporary enclosure would be installed over the excavation to contain vapors.
Treatment of vapors from enclosure. Vapors from the excavation would be collected and treated by granular activated carbon before being released into the air.
Dewatering. Since a majority of the contaminated soil is below the water table, wells would be installed to lower the water level. The extracted water would be transported offsite to an appropriate disposal facility.
On-site biological treatment of excavated material. Excavated soils would be placed on high-density polyethylene liners with a layer of sand above and one beneath the liner. The piles would be approximately six feet tall and 16 feet in diameter at the base. The contaminants in the soil would be treated by microbes naturally occurring in the soil. Adding water and nutrients and using a mechanical mixer to mix in air and to mix the microbes throughout the waste material would create the best growing conditions for the microbes. Treated soil meeting remediation goals would be returned to the excavation hole.
Leachate collection. Leachate from the piles would be collected and recycled over the soil piles to provide water to the pile and allow the contaminants in the water to be broken down by the naturally occurring microbes.
|Biological treatment of soil would take approximately 5 years. Leachate would meet remediation goals in 15 -25 years.||$18,218,000|
|SCS-7DExcavation, On-site Treatment by Low Temperature Thermal Desorption ( LTTD)|| Institutional controls, as described in SCS-7B, except a restriction on excavation would be unnecessary since the contaminated soil would be removed in about eight months.
Soil excavation. An estimated 57,000 cubic yards of soil, waste and free product would be excavated and dewatered. Due to the levels of VOCs expected to be released during excavation, a temporary enclosure would be installed over the excavation to contain vapors.
Dewatering. As described in SCS-7C.
Low temperature thermal desorption. Excavated soil would be treated on-site in a mobile low temperature thermal treatment desorption ( LTTD) unit. This unit would heat the soil to about 900(F to volatilize (vaporize) the VOCs off the soil. The contaminant vapors from the soil would be directed to (1) a baghouse where particulates such as dust would be removed, then to (2) an afterburner where vapors would be heated to 1400( to 1800(F. This high temperature would break the VOCs into harmless chemicals such as water vapor and carbon dioxide plus hydrochloric acid. A scrubber would treat the hydrochloric acid forming water and salt, and the scrubber water (pH adjusted to normal levels) discharged to a nearby drainage ditch. See enclosed fact sheet on LTTD.
Air monitoring. Air emissions from the unit would be monitored to ensure all air quality standards are met.
Treated soil returned to excavation hole. The treated soil would be tested to verify that it meets the remediation goals, cooled and rehydrated (moisture normal for soil added). Soil meeting the remediation goals would be returned to the excavation hole.
|Treatment of soil by the LTTDwould take approximately eight months. The leachatewould meet goals in 10-20 years.||$15,209,000|
SCS-7E Soil Vapor Extraction
| Same as SCS-7B plus the following:
Soil vapor extraction. Sixteen vacuum extraction wells would be constructed in the contaminated area. Since VOCs volatilize easily, suction on the system would withdraw the vapors from the air pockets beneath ground surface
Air sparging injection well system. Air would be injected into the soil and leachate, increasing the amount of VOCs that would vaporize into the air pockets in the soil above the water table.
Catalytic oxidation. The vapor from the soil vapor extraction system would be directed to a catalytic oxidation unit. This unit would break the VOCs into harmless compounds such as water vapor and carbon dioxide plus hydrochloric acid. A scrubber would treat hydrochloric acid to form water and salts, and pH adjusted water discharged to a nearby drainage ditch. See enclosed fact sheet on catalytic oxidation.
Air monitoring. Air emissions from the unit would be monitored to ensure all air quality standards are met.
|* Time to reach remediation goals
Illinois EPA and U.S.EPA propose this alternative for the Source Area 7 soil remedy.
Source Area 7
|SCL-7A No Action|| Institutional controls. A restriction would be placed on the property limiting use and access to the property until remediation goals are met.
Groundwater monitoring. Groundwater would be monitored through a system of nine monitoring wells until drinking water standards are met at the GMZ boundary.
SCL-7B Limited Actions, Multi-Phase Extraction, leachateContainment
| Same as SCL-7A plus the following:
Multi-phase extraction. A vacuum would be applied to a series of extraction wells. The vacuum would collect soil vapors, free-product and groundwater. (Vapors, free product and water are different "phases"-thus, the term multi-phase extraction).
Leachate containment. Leachate would be collected through eight containment wells constructed at the of Source Area 7 boundary to prevent the leachate from moving past the GMZ boundary.
Air stripping. Since the contaminants are volatile (they vaporize easily), they can be removed from the leachate by exposing the leachate to air and letting the contaminants evaporate. This process is called air stripping.
Catalytic oxidation unit. VOCs collected from the air stripper and from the multi-phase extraction unit would be treated by a catalytic oxidation unit as described in Alternative SCS-7E.
Air Monitoring. Discharges to the air would be monitored to ensure that they meet all federal and state laws and requirements.
Water monitoring. After the contaminants are removed from the leachate, the remaining water would be discharged to the ditch. The water would be monitored to ensure it meets all federal and state standards and requirements.
|SCL-7C Reactive barrier wall / LeachateMonitoring||Same as alternative SCL-7A plus: Reactive barrier wall. This wall would be constructed beneath ground surface downgradient of the GMZ boundary. The wall would consist of permeable iron filings. As groundwater flows through the iron, a chemical reaction would take place that breaks the VOCs down into harmless compounds.||1-10 years. The wall would have to be maintained approximately 80-90 years||$4,391,000|
|* Time to reach remediation goals
Illinois EPA and U.S.EPA propose this alternative for the Source Area 7 leachate remedy.
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 written comments received during the entire comment period plus the oral comments made at the hearing. Based on the consideration of these comments, the Illinois EPA and U.S. EPA will make a final decision on the Area 7 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 document called The 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 State of Illinois and the U.S. Department of Justice have signed a consent decree with the City of Rockford. In this consent decree, the City of Rockford agreed to pay $5 million toward the construction and maintenance of the Area 7 remedy. In exchange for this agreement, the State of Illinois and the U.S. Department of Justice agreed to release all potentially responsible parties from further liability at Area 7. Any cost over $5 million will be paid out of the federal Superfund and the Illinois Hazardous Waste Fund.
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 start construction in the 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-wide groundwater (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 7. 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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:
Community Relations Coord.
1021 N. Grand Ave. E.
Springfield, Illinois 62794-9276
Phone: (217) 524-2292
1021 N. Grand Ave. E.
Springfield, Illinois 62794-9276
Phone: (815) 223-1714
Repositories: Full reports for the project may be reviewed at the following locations.
Rockford Public Library
3128 S. 11 th Street
Rockford, IL 61109
(Call for hours)
3218 S. 11th Street
Rockford, IL 61109
(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.