Land treatment units incorporate the hazardous waste into the upper layers of the soil to allow soil microbes
and sunlight to degrade, transform, or immobilize hazardous constituents present in hazardous waste.
Treatment changes the nature of the hazardous waste so as: (1) to neutralize it, or render it non-hazardous or
less hazardous; (2) to recover it; (3) to make it safer to transport, store or dispose of; or (4) to make it
amendable for recovery, storage or volume reduction. Approximately 0.3 million tons of the hazardous waste
was treated in 1999 by Illinois hazardous waste management facilities. The residuals were handled as pollution
control wastes (415 ILCS 809). A pollution control waste is any liquid, solid, semi-solid or gaseous waste
generated as a direct or indirect result of the removal of contaminants from the air, water, or land, and which
pose a present or potential threat to human health or to the environment or with inherent properties which make
the disposal of such waste in a landfill difficult to manage by normal means. Examples of pollution control
wastes are waste water treatment plant sludges, baghouse dusts, landfill waste, scrubber sludges, and chemical
spill cleanings (415 ILCS 5/3.27).
7. Underground Injection Control
Since 1984, landfill disposal of liquid hazardous waste has been banned in Illinois (415 ILCS 5/22.6). Liquid
hazardous waste must be: (1) treated (e.g., render it so it meets sewer discharge criteria, render it non-liquid
with sorbents, etc.) and disposed; or (2) incinerated; or (3) injected into underground injection control wells.
The Illinois EPA and U.S. EPA regulate underground injection of liquid waste into deep wells (i.e., under-ground
injection control wells) to ensure that underground sources of drinking water are protected from
contamination (Safe Drinking Water Act (42 U.S.C. 300 et seq.) and Resource Conservation Recovery Act
( RCRA, 42 U.S.C. 6901 et seq.)).
Four deep underground injection control wells are permitted to dispose of liquid waste generated on-site. Three
of these wells are permitted to dispose of liquid hazardous waste and one (Equistar in Tuscola) is permitted
only to dispose of liquid non-hazardous waste.
*There are two underground injection wells at Cabot Corporation facility.
These wells are tested at least annually to ensure that they maintain mechanical integrity (i.e., there is no
significant leakage in the casing, tubing or packer or no significant fluid movement into an underground source
of drinking water). If a well should fail a mechanical integrity demonstration, it will be shut down immediately
until corrective actions are complete and the well has been brought back into compliance. The conditions of the
permit limit the injection pressure to ensure safe operation of the well.
8. Contaminated Sites
Successful completion of cleanup program requirements results in a completion letter. The table on the next
page shows the type of completion letters issued by the Illinois EPA cleanup programs.
Facility Illinois Identification Number Location
Cabot Corporation* 0418080001 Tuscola
LTV Steel 1558010006 Hennepin
Equistar 0418080002 Tuscola
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