Statistical comparison of leachate from hazardous, codisposal, and municipal solid waste landfills

There has been considerable debate regarding the chemical characterization of landfill leachate in general and the comparison of various types of land fill leachate (e.g., hazardous, codisposal, and municipal) in particular. F or example, the preamble to the U.S. EPA Subtitle D regulation (40 CFR Part s 257 and 258) suggests that there are no significant differences between t he number and concentration of toxic constituents in hazardous versus munic ipal solid waste landfill leachate. The purpose of this paper is to statist ically test this hypothesis in a large leachate database comprising 1490 le achate samples from 283 sample points (i.e., monitoring location such as a leachate sump) in 93 landfill waste cells (i.e., a section of a facility th at took a specific waste stream or collection of similar waste streams) fro m 48 sites with municipal, codisposal. or hazardous waste site histories. R esults of the analysis reveal clear differention between landfill leachate types, both in terms of constituents detected and their concentrations. The result of the analysis is a classification function that can estimate the probability that new leachate or ground water sample was produced by the di sposal of municipal, codisposal, or hazardous waste. This type of computati on is illustrated, and applications of the model to Superfund cost-allocati on problems are discussed.