Environmental Engineering Reference
In-Depth Information
11.5.2
C ONTAMINANT L EACHABILITY
The RCRA requires the USEPA to classify wastes as either hazardous or non-
hazardous. Under the regulations implementing Subtitle C of RCRA, wastes are
designated as hazardous in two ways:
Solid wastes that exhibit certain characteristics, as listed in 40 CFR Part
261, Subpart C
Solid wastes that are specifically listed as hazardous in 40 CFR Part 261,
Subpart D
The generator is responsible to use TCLP to find out whether or not a solid
waste exhibits a hazardous waste characteristic. Table 11.5 lists the contaminants of
concern and their concentration limits as regulated in 40 CFR 261.24. 107
TCLP is being used as the regulatory leaching test in many regions and countries.
The Province of Alberta, Canada, adopted TCLP as a regulatory test in 1996.
Although other countries may use TCLP as a regulatory test, their regulated con-
taminants and levels may be different. For example, Ontario Regulation 558/00 108
adopted the USEPA TCLP testing procedure in 2000, but added 15 new inorganic
and 73 new organic contaminants.
The RCRA regulations in 40 CFR 260.20 and 260.22 contain provisions that
allow the petitioning of the governing agency to exclude or “delist” a listed hazardous
waste from the universe of regulated hazardous wastes. In the past, delisting was
considered virtually unachievable and economically unfeasible. In 2000, the USEPA
published the EPA RCRA Delisting Program Guidance Manual for the Petitioner , 109
which provides a streamlined framework to petitioners and makes the delisting
application much easier. The USEPA evaluates the potential hazards of waste through
the use of appropriate fate and transport models, which calculate possible exposure
to hazardous chemicals that might be released from petitioned wastes after disposal,
based on a reasonable, worst-case management scenario. A major concern is inges-
tion of contaminated groundwater. To evaluate this concern, the agency typically
relies on leachate data as determined by TCLP. The leachable concentrations and
the estimated waste volume then are used as inputs to an appropriate fate and
transport model, for example, EPA's Composite Model for Leachate Migration with
Transformation Products (EPACMTP), 110 to predict the constituent concentrations
in the groundwater at a hypothetical exposure point. The calculated exposure-point
concentrations are typically compared to drinking water standards or other EPA
health-based levels.
Section 6.2.2 of the Guideline 109 provides guidelines for stabilized wastes. If the
petitioned waste is generated from the chemical stabilization of a listed waste, then
leachable metal concentrations should be tested using the Multiple Extraction Pro-
cedure, SW-846 Method 1320, as well as by TCLP analyses to assess the long-term
stability of the waste.
The majority of delisted wastes are metal-bearing wastes (such as F006 and
F019 wastewater treatment sludges and treated K061 electric arc furnace dusts). Any
Search WWH ::




Custom Search