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binders (e.g., phenol formaldehyde, phenol isocyanate, alkyl isocyanate). The typical solid waste of a
foundry is two thirds or more system sand, 2 to 20% core sand and core butts, and up to 11% dust collected
in the baghouse that is used for air pollution control.
These wastes are generally put into landfills. Most of the waste is inert (sand) but certain compo-
nents have the potential of being leached from the landfill and entering subsurface soils and ground-
water. Studies of leachate from foundry landfills have shown large variations in chemical composition.
The variation may arise from the nonuniformity of the waste materials deposited in the landfill, but it
also may have other causes. This raises questions about how large a sample should be collected in the
field, and whether this sample should be a composite of many small portions. There are also questions
about how to partition a large field specimen into smaller portions that are suitable for laboratory analysis.
Finally, the laboratory work itself cannot be overlooked as a possible source of variability.
These considerations point to the need for replicate specimens and replicate measurements. An efficient
protocol for sampling and analytical replication cannot be designed until the sources of variation are
identified and quantified. The major source of variation might be between field specimens, from sub-
specimens prepared in the laboratory, or from the analytical procedure itself.
Krueger (1985) studied three kinds of solid waste (system sand, core butts, or baghouse dust) from a
foundry. One of his objectives was to assess the magnitude of the variance components due to (1) batch
of material sampled (system sand, core butts, or baghouse dust); (2); specimen preparation in the laboratory
(which includes a leaching extraction performed on that specimen); and (3) the analytical test for a specific
substance. One of the substances measured was copper. Table 25.2 is an abridgment of Krueger’s data on
copper concentrations in a leaching extract from the three batches of solid waste.

TABLE 25.2
Copper Concentrations in the Leachate Extract of Foundry Solid Waste
Copper Concentrations (mg// //L)
Batch of Specimen Specimen Specimen Ave. Batch Ave.
Solid Waste Number y bst y bs y b
Baghouse dust 1 0.082
0.084 0.0830
2 0.108
0.109 0.1085
3 0.074
0.070 0.0720
4 0.074
0.071 0.0725 0.0840
Core butts 1 0.054
0.051 0.0525
2 0.050
0.050 0.0500
3 0.047
0.050 0.0485
4 0.092
0.091 0.0915 0.0606
System sand 1 0.052
0.050 0.0510
2 0.084
0.080 0.0820
3 0.044
0.041 0.0425
4 0.050
0.044 0.0470 0.0556
Source: Krueger, R. C. (1985). Characterization of Three Types of Foundry Waste and Estima-
tion of Variance Components, Research Report, Madison, WI, Department of Civil and Envi-
ronmental Engineering, The University of Wisconsin–Madison.
© 2002 By CRC Press LLC