Page 550 - Materials Chemistry, Second Edition

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17 Land Disposal of Hazardous

Waste

Farther off, farther off, the burying ground.
I wish you peace.
I wish the labyrinth of byways may one day be lost
beneath the new green of Spring.
Gu Cheng (1956–1993)
Yes, I go also

17.1 INTRODUCTION
About 23 million tons of hazardous wastes are land disposed each year (U.S. EPA, 1999). Land dis-
posal can take place on or slightly below the ground surface, i.e., in a landfill or other land-based
unit, or can occur under the Earth’s surface, for example, by deep-well injection.
As will be apparent in this chapter, modern land-based disposal systems for hazardous wastes
are designed and equipped with numerous safeguards and are closely regulated; however, if a haz-
ardous waste is not properly treated before disposal, it can still contaminate local soil, groundwater
and surface water. Additionally, rainwater, snowmelt, and groundwater can penetrate a landfill and
disposed hazardous waste and can potentially mobilize hazardous substances.

17.2 THE LAND DISPOSAL RESTRICTIONS REVISITED

The land disposal restrictions were originally divided into five deadlines, or phases, mandated by
federal law. Each phase restricted different types of hazardous waste from land disposal by a spe-
cific deadline. Phase One, for dioxin-containing wastes and spent solvents, was put into effect by
1986 (40 CFR Parts 268.30 and 268.31). Spent solvents and dioxin-containing wastes were the first
wastes restricted from land disposal because they are generated in the greatest quantities and can be
extremely hazardous. These wastes include F001–F005 solvents and F020–F023 plus F025–F028
dioxin wastes listed in 40 CFR Part 261.31. F-listed wastes are those from nonspecific sources and
are commonly produced by manufacturing and industrial processes.
Phase Two, the so-called California List, was put in effect by 1987. This was dubbed ‘The
California List’ because California was the first state to restrict land disposal of these hazardous
wastes. Phase Two restricts land disposal of untreated, liquid hazardous waste containing the fol-
lowing constituents:

● Polychlorinated biphenyls (PCBs)
● Corrosives with pH < 2 or free cyanides
● Arsenic, cadmium, chromium (VI), lead, mercury, nickel, selenium, and thallium

The California List also restricts hazardous waste containing halogenated organic compounds
in liquid or nonliquid form (40 CFR Part 268.32). After the Phase One wastes, California List
wastes are the next most abundant and hazardous.

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