32    LINER SYSTEMS FOR INDUSTRIAL WASTE LANDFILLS
Robert J. McLaren, Consulting Engineer
Dale A. Krysinski, Chief Environmental Engineer
SE Technologies, Inc.
Bridgeville, Pennsylvania 15017
INTRODUCTION
Landfill design standards have evolved in the last few decades to provide disposal sites that protect
ground water from degradation. The two principal types of wastes that have received the greatest
attention have been:
1. municipal waste —because it is widespread, highly visible and putrescible
2. hazardous waste —because of the severe environmental problems that have resulted
from improper handling and disposal in the past.
However, non-hazardous industrial waste constitutes the largest volume of solid waste generated.
For example, in Pennsylvania, about 64 percent of all waste is non-hazardous industrial waste, while
only about 33 percent is municipal, and only about 3 percent is classified as hazardous. Although
disposal standards specifically for non-hazardous industrial wastes have been a lower regulatory
priority, such standards have been recently developed. As might be expected, greater attention to
industrial wastes has been given in those states that produce large volumes and are densely populated.
Thus, Pennsylvania, Ohio and Indiana have all recently promulgated or are proposing new standards
for industrial waste landfills.
A review of the approach being following in each of these states shows similarities as well as distinct
differences. It is worth reviewing the evolving standards in each of these states as an indicator of
trends in the Midwest, as well as trends which are likely to be followed in other regions. Principal
features of the regulations in each of these states includes a system of waste classification to assess the
potential of a waste material to cause environmental problems. Based on this assessment, a spectrum
of standards for liners is included in the regulations that are based primarily on the nature of the waste
being contained. The most stringent standards are applied to those wastes judged to have the greatest
potential for adverse environmental impacts.
WASTE CLASSIFICATION SCHEMES
Waste classification schemes in all three states are based on the realization that wastes vary in their
potential for adverse environmental impacts. Actually, the regulations in all three states classify waste
sites to define the limits of chemical properties that are acceptable for disposal in each class, rather
than actually classifying the individual wastes. Although the waste sites are categorized and not the
wastes themselves, the net effect is the same. Thus, the regulations reflect the realization that there is a
spectrum of waste types that range from the nearly hazardous to the relatively environmentally
benign. Classification for landfills varies across this spectrum as well.
Wastes are evaluated based on their perceived potential to cause ground water contamination. The
classes of landfills are based on the degree of containment required and their potential to prevent
adverse environmental impacts from the wastes contained. The waste classification systems are based
on a comparison of laboratory leachate test results to water pollution standards such as those used to
evaluate drinking water. Wastes which produce leachates with water quality close to drinking water
standards are judged to have a low potential for adverse environmental impacts and may be disposed
of in sites with the lowest level of containment. Those wastes that have leachate values which are
substantially above drinking water standards are to be placed in sites having the greatest degree of
containment. Although the approach is similar, the test method and standard of comparison varies in
each of the states. All three states have taken the approach of basing divisions between waste
categories on research done in developing drinking water standards. However, Ohio and Indiana have
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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