REMOVAL OF SELECTED TRACE ELEMENTS FROM ACID
MINE DRAINAGE USING EXISTING TECHNOLOGY
Roger C. Wilmoth, Sanitary Engineer
Thomas L. Baugh, Engineer
Dean Wm. Decker, Biologist
Extraction Technology Branch
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
INTRODUCTION
The presence of trace elements in acid mine drainage (AMD) has received little
attention in the past; however, recent cognizance has prompted the research community
to address the situation.   AMD offers a favorable medium for existence of trace
elements because many are acid-soluble and are leached from strata associated with
the mining process.   Some trace elements are on the U.S. Environmental Protection
Agency list of Priority Pollutants.
The purpose of this study was to determine the effectiveness of lime neutralization,
reverse osmosis, and ion exchange treatment processes in removing several of the trace
elements.    The study was conducted at the EPA Crown Field Site, which is located
near Morgantown, West Virginia.    At Crown, appropriate concentrations of trace
elements could be injected into a moderately acid AMD stream to simulate the field
situation.
The selection of the parameters to be studied and their respective concentrations was
made on the basis of levels found in mine discharges.   Table I illustrates the matrix of
data used in the selection.    These choices are summarized in Table II.    Eight of the
10 are listed by EPA as toxic substances.   For this study the 10 compounds were
combined in one concentrated bulk solution and were continuously injected into the
AMD feed streams to the neutralization, reverse osmosis, and ion exchange processes
to form the desired concentrations.    Some precipitation problems were encountered
during lab-scale concentrate preparation, necessitating substituting different compound
forms of two elements and eliminating lead from the original study list.    Table II
contains the final choice of compounds.
TREATMENT STUDIES
Background Information
Lime neutralization, reverse osmosis, and ion exchange were studied to determine
their effectiveness in removing the  10 trace elements of interest.    EPA awarded a contract to Hydroscience, Inc., a subsidiary of Dow Chemical, to provide analytical services
for the trace element analyses and to provide technical assistance.   Most of the work
summarized in this paper was excerpted from an upcoming final report by Wilmoth,
Scott, Hall, and Stuewe, which will be published early in 1979.   EPA Methods were
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