24    APPLICATION OF AUTOMATIC BACKWASH PREFILTER
WITH CARBON ADSORPTION FOR PETROLEUM
HYDROCARBON CONTAMINATED GROUNDWATER
TREATMENT
Samuel S. Hu, Project Engineer
Matthew J. Germane, Engineering Department Manager
Delta Environmental Consultants, Inc.
Farmington Hills, Michigan 48331
INTRODUCTION
Recovery and treatment of petroleum hydrocarbon contaminated groundwater at two petroleum
product underground storage tank (UST) sites in Michigan are being conducted using groundwater
recovery wells and two-stage granular activated carbon (GAC) adsorption systems. The first system,
System 1A, designed with cartridge filters for suspended solid and total iron removal and two-stage
GAC adsorption cells for petroleum hydrocarbon removal, was installed at Site 1 in 1989. The
automatic backwash prefilter system for suspended solid and total iron removal in System IB was
designed and added to System 1A at Site 1 in April 1992. The second system, System 2, was designed
and installed with automatic backwash prefilter and two-stage GAC adsorption cells at Site 2 in 1992.
BACKGROUND
UST Laws in Michigan
The Michigan leaking underground storage tank statutes have been developed to provide the state
government with regulatory authority necessary to prevent and control environmental contamination
resulting from UST releases. A UST "release" is defined as any spill, leak, emitting, discharge, escape,
leach, or disposal from a UST system into groundwater, surface water or subsurface soils. A petroleum product release can cause many damages to the environment. One of the damages, most often, is
to groundwater. In Michigan, nearly 50% of the people use groundwater for their source of drinking
water, and only one gallon of gasoline can contaminate a million gallons of groundwater (1,000 jig/L
approximately).1
The state UST laws were largely fashioned after Subtitle I of the federal Resources Conservation
and Recovery Act (RCRA). As a result of the legislation, over 71,000 USTs have been registered at
more than 22,000 facilities, and more than 3,500 sites contaminated by leaking USTs have been
identified in Michigan.1
Groundwater contamination is usually caused by a confirmed petroleum product release at a UST
site. A confirmed release is identified when either physical evidence or laboratory results indicate that
contaminants are present in groundwater or soil. Laboratory analysis which indicates quantities of
contaminants in a sample above the acceptable regulatory concentrations is proof of a confirmed
release.
A release can be discovered in a variety of ways, ranging from smelling petroleum in groundwater
or soil during a tank closure to finding petroleum products in monitoring wells during a regular
system inspection. Also UST site neighbors may complain that their well water tastes or smells bad, or
they notice a strange odor in their basement.
When a release from a UST system is discovered, it is critical that the owner/operator of the UST
system comply with the UST laws and remediate any contamination. Potential civil penalties, in
addition to court awarded damages for noncompliance of a release-confirmed UST system, could be
charged to the owner/operator if the owner/operator failed to carry out the required corrective
actions.
48th Purdue Industrial Waste Conference Proceedings, 1993 Lewis Publishers, Chelsea, Michigan 48118. Printed in
U.S.A.
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