7    INTERCEPT TRENCH TECHNOLOGY FOR REMEDIATING
WASTE OIL CONTAMINATED SOIL AND
GROUNDWATER: A CASE STUDY
David A. Piotrowski, Hydrogeologist
Karl W. Yost, Director/Technical Services
MAECORP Incorporated
Homewood, Illinois 60430
INTRODUCTION
Perched groundwater contaminated with waste oil was effectively recovered from low permeability
clay till soil with an intercept/recovery trench system. Site activity conducted prior to trench installation included tank removal, soil excavation and disposal, soil and groundwater sampling, and mobile
treatment of pit-impounded oil and water. Periodic sampling and analysis of soils and groundwater
conducted during cleanup support the effectiveness of remedial design and implementation.
REGIONAL GEOLOGY
The geology in the region of the site consists predominantly of Pleistocene, Wisconsinan age glacial
deposits.1 The glacial materials surrounding the site were likely deposited as a result of mass ice
melting resulting in morainal till deposits and intermorainal or lake plain lacustrine deposits. The
morainal soil in the region is chiefly composed of clay rich till materials with occasional sand or silt
rich layers and lenses. The intermorainal/lacustrine deposits consist mostly of silt and clay formations
with occasional peat beds.
The local bedrock is composed of Ordovician, Niagran dolomite and is generally buried below
approximately 100 feet of glacial material. The bedrock does occasionally outcrop in the area.2
BACKGROUND
Tank Excavation
Four underground storage tanks were excavated and removed from the area depicted on Figure 1.
The 10,000-gallon tank contained diesel fuel and was resting on clay at a depth of approximately 10
feet below grade. The two 500-gallon tanks and the 1,000-gallon tank each contained waste oil and
were buried to a depth of approximately 5 feet below grade.
During excavation of the tanks, groundwater contaminated with waste oil migrated freely into the
pits from the east, north, and west walls. In addition, contaminated soil was observed at the base of
the excavation as well as along the excavation walls. Approximately 2,100 cubic yards of soil grossly
Figure 1.    Site layout.
44th Purdue Industrial Waste Conference Proceedings, © 1990 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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