Foams, spray-on slurries, and geosynthetics are popular ways to cover landfills at closing time. Called alternative daily covers (ADC), they “control disease vectors, fires, odors, blowing litter, and scavenging,” as intended by EPA guidelines for landfill daily cover. In addition, ADCs can save landfill space, reduce operating cost, promote markets for recycling or waste-derived materials, and provide an alternative to adverse impacts sometimes associated with soil for daily cover.

A new standard from ASTM Committee D35 on Geosynthetics explains the performance and effectiveness of various ADCs. Waste disposal regulators, engineers, and operators who reference ASTM D 6523, Standard Guide for Evaluation and Selection of Alternative Daily Covers (ADCs) for Sanitary Landfills, will understand:
--ADC features, uses, available options; and
--Considerations to meet EPA requirements.

Two six-column tables cover application, equipment maintenance, removal, inclement weather constraints, disease and fire control, odor emission, water infiltration, landfill leachate/gas migration interference, and life expectancy of five categories of ADCs:
--Foams;
--Spray-on slurries;
--Re-usable geosynthetics;
--Non re-usable geosynthetics; and
--Indigenous materials.

“The ADC standard guide should be a great assistance to landfill managers and engineers to make appropriate selections among the many different materials being offered for ADCs,” says Mark Cadwallader, president, Cadwallader Technical Services, Conroe, Texas. “The guide provides a great deal of information. The table summarizing features and performance considerations should allow a quick assessment for purchasing and specification decisions.”

The standard was developed with the combined effort of manufacturers, testing laboratories, consultants, researchers, government agencies, and design engineers in a task group of ASTM Subcommittee D35.03 on Permeability and Filtration, chaired by Cadwallader.

For further technical information, contact Mark Cadwallader, Cadwallader Technical Services, 598 Rolling Hills Rd., Conroe, TX 77303 (409/264-2004). Committee D35 meets Jan. 22-25 in Reno, Nev. For meeting or membership details, contact manager Pat Picariello, ASTM (610/832-9720). //

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