Information for Landfills in the Site Remediation Program

This information is provided to assist Remedial Applicants enrolling former landfills into the Voluntary Site Remediation Program (“VSRP”). First, we must distinguish between VSRP eligible and ineligible landfills.

According to Section 58.1(a)(2) of the Environmental Protection Act (“Act”) and 35 Illinois Administrative Code (“IAC”) 740.105(a)(2), the following waste disposal sites cannot enter into the VSRP:

1. Permitted landfills subject to closure and post-closure requirements are clearly not eligible for the VSRP. However, a disposal site is eligible for the VSRP after it completes all its post-closure requirements. For example, a landfill that initiated 30 years of post-closure requirements on October 11, 1993, completes them on October 10, 2023, and is issued a certification of completion of post-closure care is VSRP eligible at that time. 

2. Disposal sites subject to closure and post-closure requirements under federal or state solid or hazardous waste laws are not eligible. This includes landfills that have ceased accepting waste, but are still undergoing their 15-year or 30-year post-closure requirements.

Ineligible landfills include closed solid waste facilities that are still subject to post-closure care, such as groundwater monitoring and cap maintenance.

Once a site is permitted and regulated as a landfill, it continues to be subject to regulations until all the closure and post-closure requirements are met. That is, a permitted landfill that has only received a closure certification, is still required to complete post-closure care requirements for a minimum regulatory prescribed period of time and thus is not VSRP eligible. Prior to the 35 IAC 807 rules (effective July 27, 1973) there were no post-closure requirements, other than two feet of final cover to be placed onto the landfill and the surface of the final cover to be maintained at the plan elevation at all times.

In summary, the VSRP does not replace otherwise applicable environmental landfill regulations. The Illinois EPA’s Bureau of Land Permit Section determines if a regulated landfill has met all of its closure and post-closure care requirements, and if a site is still ”active.”

If the site is not receiving wastes and the site has fulfilled closure, and post-closure requirements, then the site may apply for the VSRP. Landfills eligible for the VSRP are typically:

1. Former dumps that operated prior to state permitting requirements, and are not subject to post-closure requirements (e.g. sites closed prior to 1970); 

2. Closed solid waste facilities that have fully met all their permit and post-closure requirements (e.g., sites closed after 1970); or 

3. Contaminated sites and dumps that are not regulated as a landfillThe remediation site is on the National Priorities List (Appendix B of 40 CFR 300);

The third category of contaminated sites and unpermitted dumps that are not regulated as a landfill is difficult to determine. Most contaminated sites in the VSRP have historical, on-site releases and did not actively receive off-site wastes for disposal. Therefore, the Remedial Applicant must evaluate the site in terms of all applicable County and State environmental requirements, including: the landfill regulations from Section 21 of the Act (35 Ill. Adm. Code 807 and 811 rules); the Steel and Foundry Sand regulations from 35 Ill. Adm. Code 817: the Construction and Demolition Debris regulations from Sections 3.78 and 3.78(a) of the Act; and Section 3.94 for Coal Combustion By-product Waste Used Beneficially.

A further distinction is whether a site received contaminated fill. If the site did receive contaminated fill, and the fill is not or was not waste, then the site is potentially eligible for the VSRP. Conversely, a person could be subject to an Open Dumping violation (see Section 3.24 of the Act). That is, solid-waste disposal permits are required for sites which receive or dispose of waste.

While determining if a site is eligible for the VSRP, the Remedial Applicant should evaluate the practicability of achieving their goals for enrolling a landfill into the VSRP.

The Remedial Applicant should evaluate if securing the property’s end use (residential use, industrial/commercial use, open space, etc.) is feasible, and if the property’s end use is compatible with the types of institutional controls or ordinances that may be necessary. Most former dumps and landfills will warrant a Tier 3 (Part 742.910, 742.915, 742.920 or 742.925) evaluation.

The Remedial Applicant should evaluate the limitations of four ceiling criteria using 35 Ill. Adm. Code Part 742, specifically: (1) soil attenuation, (2) soil saturation, (3) TCLP for characteristically hazardous waste, and (4) removal of free-product in groundwater. If a site cannot meet these four requirements, it is unlikely a No Further Remediation letter will be issued.

The Illinois EPA’s VSRP is committed to a performance-based approach for all site investigations, site cleanups, and risk management. The following Phase I and Phase II guidance provides how the Illinois EPA will evaluate a VSRP eligible landfill

The Phase I Assessment should include the following information:

1. History and Dates of Operation . When did the landfill begin and cease accepting waste? When did post closure activities, if applicable, start and end?
2. Regulatory History . Dates of any applicable permits and certifications and any court or Pollution Control Board orders.
3. Landfill Limits . What is the waste footprint estimated from historical air photographs, former on-site personnel, operating landfill designs, etc.?
4. Types of Waste . What types of municipal, industrial, liquid, ash, etc., wastes were received?
5. Cover Material . A visual check of the cap type and thickness, as well as the historical documents should be reported. What is the current vegetation cover? Provide current photographs of the cover.
6. Facility’s Physical Geography . A visual check of terrain, drainage patterns, creeks, low spots, flooding, etc., should be reported.
7. Potable Water Supply Wells . The location and depths of potable water supply wells (both public and private) should be identified.

The Phase II Assessment will conduct field testing to prepare a thorough investigation report. Prior to conducting a field investigation, providing the on-site investigative worker’s safety is of utmost concern. Safety hazards exist whenever waste is exposed or excavated, or pockets of explosive or toxic gases are released. Workers who will be in contact with waste are to be made aware of the potential dangers involved, and given instructions on how to deal with the possibility of coming into contact with hazardous or toxic wastes and gases. The use of the proper personal protective equipment such as gloves, clothing and respirators is to be emphasized. The use of spark-less equipment may be necessary. A plan addressing safety concerns must be in place prior to any field investigative work.

The Phase II Investigation Report should include the following information:

1. Cap Quality and Thickness . The cap quality and thickness should be determined. Soil samples should be collected to determine the geology, permeability, and hydraulic conductivity of the on-site soils. Test pits can be used to determine the thickness of the cap.
2. Cap Slope . The potential for erosion should be measured and evaluated.
3. Landfill Contents and Limits of Waste Footprint . Test pits and/or soil borings provide information on the types of wastes, waste depths and lateral limits of the waste pile, as well as the landfill’s moisture and leachate potential. The visual observations of each test pit will be documented. During the site characterization, care must be taken to avoid puncturing or breaching the underlying clay foundation. During the site characterization phase, drill rig borings should avoid puncturing or breaching the underlying clay foundation, as the landfill may have accepted liquid waste.
4. Leachate . Leachate should be analyzed for chemical constituents including volatiles, inorganics, and semi-volatiles, as well as pH, BOD, and COD.
5. Gas Generation Potential . The concentrations of methane, carbon dioxide, and oxygen should be evaluated from wells screened directly into the waste. If all of a landfill’s contents consist of non-organic material, then gas generation concerns will be minimal. The Illinois EPA may request toxic gases be analyzed, such as hydrogen sulfide and other manmade organic compounds. More than one gas reading, over a period of time, should be collected to account for atmospheric pressure trends and precipitation events. If methane values are found to be greater than 25 percent of the Lower Explosive Limit (LEL), (the LEL is 5% percent methane by volume, so 25% of the LEL is 1.25%), then an Illinois EPA exemption cannot be obtained for new a building on top of the landfill, regardless of the proposed engineering controls. That is, the Illinois EPA would likely not issue a No Further Remediation letter stating it is safe for constructing a new building on top of a gas-producing landfill, if the methane concentrations are found to be greater than 25% of the LEL. If the methane concentrations are less than 25% of the LEL but greater than 0%, then the installation of vents, trenches, methane alarms, and construction with slab foundations may prevent the migration of methane into buildings.
6. Settlement Issues . Over time, the waste in a landfill settles unevenly. If the landfill consists of non-organic wastes then settlement may not be of concern. For example, a flyash landfill would be expected to settle very little, provided it was properly compacted during placement. But, a municipal solid waste landfill with high amounts of organic waste, settles at greater rates due to the degradation of the organic matter. A building’s structure and foundation may crack and create routes for gases to enter a building due to the differential settlement of a landfill; or the building can become unsafe due to structural instability. Furthermore, utility lines may crack or break due to a landfill settling. A sewer line crack will allow contaminated liquids to enter the waste pile or the water table. Additionally, caissons and pilings used to stabilize foundations can create conduits for landfill gases and leachate, because the space between the pilings and the soil is not air tight and the gases and leachate can migrate in toward the building. Depending on a site’s geology, the pilings might completely penetrate the waste pile and extend into a non-contaminated aquifer, possibly allowing contaminants to migrate into the lower aquifer.
7. Geology . Local hydrogeology information is to be determined, including the groundwater depth, flow direction and groundwater quality.
8. Groundwater Assessment . Installation of monitoring wells will be needed on and off-site to determine the extent, if any, of contamination. A groundwater model may be necessary to map the potential future groundwater impacts.
9. Manmade Migration Pathways . Information is to be gathered of the existing underground utility lines that could be acting as a conduit for landfill gases and leachate. Utility trenches are usually backfilled with granular soils or rocks that create routes for gases to migrate and for surface water to travel into the waste and create additional leachate. These permeable trenches may also create conduits for gas and leachate to leave the landfill area. It is anticipated the Illinois EPA’s No further Remedial Letter will not prohibit new underground utilities to be placed through a landfill, provided a worker caution is provided and the permeable routes are corrected.

If you have questions concerning the eligibility of a landfill to enter the Site Remediation Program, please contact the Illinois EPA’s Site Remediation Program at 217-524-3300.

Revised September 1, 2006