30 Sep 01
(3) Leachate. To evaluate what disposal options are available for landfill leachate, it is necessary
to determine the leachate characteristics. For preliminary design, the total organic loading
(BOD/COD), nutrient loading, suspended solids, and hazardous constituents (e.g., heavy metals,
VOCs, etc.) should be determined.
(4) Ground Water. Ground water characteristics, if unknown, must be analyzed both up-
gradient and down-gradient of the landfill. Chemical analysis required may vary, depending on
applicable regulatory requirements.
(5) Determination of Landfill Limits. Although the limits of the waste materials are often easily
determined by visual observation during trenching activities, additional soil testing for site contaminants is
sometimes required to better define the limits of the waste materials.
(6) Contaminated Materials Handling and Disposal. To evaluate the safest way to handle the
waste material during construction (e.g., waste regrading), it is necessary to know what contaminants
are present. Also, this information is required to properly dispose of contaminated materials removed
from the site.
(7) Decontamination Water. Chemical analysis of the water used to decontaminate equipment
at the site must be specified in the contract documents so that disposal options can be determined.
(8) Air Monitoring. Air monitoring may be required for some operations during the construction
of the landfill cover and should be included in the contract documents. Site operations may need to be
modified if off-site air emissions are above regulatory limits.
(9) Contaminated Surface Water Runoff. Provisions should be made in the contract docu-
ments for the collection of storm water runoff that has come into contact with contaminated materials.
The collected water should be tested for contamination so that disposal options can be determined.
B-3. Cover System Components.
a. General. The following design guidance satisfies the requirements of 40 CFR 264 and 265.
Other final cover designs may be acceptable, depending upon site-specific conditions and upon a
determination by regulators that an alternative design adequately fulfills the regulatory requirements. The
components of a hazardous waste landfill cover generally consist of an erosion control layer, a
protective soil layer, a drainage layer, a barrier layer, and a random fill layer overlying the waste. A gas
collection system can also be a component of a landfill cover, if landfill gas is found to be present.