PB98-963152
EPA 541-R98-179
March 1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Lorentz Barrel & Drum Co.
San Jose, CA
4/24/1998
-------
Explanation of Significant Differences
Lorentz Barrel and Drum Superfund Site
1515 South Tenth Street
San Jose, California
I. Introduction
This document presents the explanation of significant differences ("ESD") for a proposed
change to the remedy chosen in the Operable Unit 2 Record of Decision ("OU-2 ROD") for the
Lorentz Barrel and Drum Sujjerfund site (the "Site"). The OU-2 ROD was dated September 22,
1988, and addressed the remediation and monitoring of the shallow groundwater contamination
which resulted from activities at the Site.
The Site is located at 1515 South Tenth Street in San Jose, California. The lead agency
for the Site is the United States Environmental Protection Agency, Region EX ("EPA"). Support
agencies include the Regional Water Quality Control Board, San Francisco Bay Region
("RWQCB") which is located in Oakland, California and the California Environmental
Protection Agency, Department of Toxic Substances Control ("DTSC") which is located in
Berkeley, California.
Preparation and public notice of this ESD is required pursuant to section 117{c) of the
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), 42
U.S.C. section 9617(c). This ESD will become part of the administrative record (the
"Administrative Record") for the Site. The Administrative Record is available for review in
several repositories including the San Jose Main Library, Reference Desk, 180 West San Carlos
Street, San Jose, California during normal library hours.
Currently, the groundwater is being extracted from a series of extraction wells located
both on and off the Site. The extracted groundwater is pumped to an on-Site treatment facility.
At the treatment facility the contaminated groundwater is first treated in an ultra violet/oxidation
unit ("UV/Ox"). The UV/Ox unit subjects the groundwater to ultra violet light and oxidizing
chemicals (ozone) which converts volatile organic compounds ("VOCs") in the contaminated
groundwater into less toxic compounds. However, due to a lack of efficiency of the UV/Ox
system in destroying several of the organic contaminants, the contaminated groundwater is then
filtered through a series of granular activated carbon ("GAC") filters, and treated to levels below
allowable discharge limits. The treated groundwater is then discharged to a local storm sewer.
Concentrations of organic contaminants at the Site have generally decreased since
commencement of the groundwater treatment system in 1992. Based on the reductions in the
concentrations of organic contaminants in the groundwater being extracted at the Site, and the
inefficiency of the UV/Ox unit in its ability to reduce these organic contaminants to the discharge
-------
limits, the potentially responsible parties ("PRPs") implementing the groundwater remediation
program have requested that EPA approve a change to the current treatment system involving the
removal of the UV/Ox treatment unit from the approved treatment program. The revised
treatment system would consist of subjecting the contaminated groundwater to the GAC filters,
exclusively.
II. Background
From 1947 to 1987, an operation existed at the Site wherein drums would be received on-
site and rinsed and/or reconditioned. The drums often contained substances such as organic
solvents, pesticides, acids, bases, oxidizers, and oils. Many of the substances were discharged to
a drainage ditch and on-site sumps, eventually making their way to a nearby creek.
Site investigations indicated that on-site operations resulted in organic and inorganic
contamination of the local shallow groundwater. These contaminants included trichloroethene
(TCE), trichloroethane (TCA), tetrachloroethene (PCE), dichloroethene (DCE), dichloroethane
(DCA), vinyl chloride, and others.
!n September 1988, the OU-2 ROD was signed by EPA. Subsequently, in 1990, a group
of PRPs for the Site agreed to implement the remedy selected in the OU-2 ROD. This agreement
was memorialized in a Partial Consent Decree between the United States and the PRPs. The
Partial Consent Decree was approved by the Northern District of California on July 6, 1990
(Civil No. C 90 0488 EFL). This ESD addresses differences to the remedy selected under the
OU-2 ROD.
The OU-2 ROD addressed an Expedited Response Action (ERA)/Operable Unit for
treatment of the contaminated shallow groundwater. The remedy selected in the OU-2 ROD
addressed the principal near-term threats to groundwater in the Site vicinity. The threat cf
contamination of the deep drinking water aquifer and nearby surface water bodies was addressed
by extracting the contaminated shallow groundwater and treating it to action levels prescribed by
the Applicable or Relevant and Appropriate Requirements (ARARs).
The major components of the shallow groundwater remedy chosen in the OU-2 ROD
included:
• construction and operation of a groundwater extraction system to intercept several
shallow groundwater plumes;
• construction and operation of a groundwater treatment system; and
• disposal of treated groundwater to the storm sewer, which flows to Coyote Creek.
-------
The selected groundwater treatment system included a commercially available packaged
ultra violet light/ozone system to destroy VOCs. If necessary, an ion exchange column would be
added to remove nickel. Treatability studies of the UV/Ox unit conducted at the Site in August
1988 determined that a GAG polishing unit was not necessary in order to meet the cleanup
standards. However, startup operations of the UV/Ox unit following signing of the OU-2 ROD
in September of 1988, indicated that the GAC polishing process was needed in order to meet the
cleanup standards, and became part of the groundwater treatment system. The ion exchange
column was found not to be necessary.
III. Basis for Differences
Since operation of the combined UV/Ox - GAC treatment system began in May 1992, the
PRP's have reported that the UV/Ox unit has operated at a less than expected level of efficiency
and higher than expected costs. According to the PRP's, the UV/Ox unit has operated at a
destruction efficiency of less than 75%. The greatest effect on efficiency appears to be scaling of
the reactor lamps due to carbonate in the water. High electrical costs for operating the unit
($26,000 per year), the need for storing and handling hazardous materials such as acids, bases,
and peroxide, and the high maintenance requirements make operation of the unit a less desirable
option than the operation of the GAC system alone.
Performance testing on the UV/Ox unit was conducted by the PRP's in July of 1997. The
results were presented in a report dated July 25,1997, titled "Performance Testing Report,
Shallow Ground Water Treatment System, Lorentz Barrel and Drum Site" prepared by Harza
Engineering Company. A copy of this report is available in the Administrative Record. The
report indicated that no combination of pH adjustment, peroxide addition, lamp maintenance, or
number of lamps used in the UV/Ox unit proved more cost effective or efficient than use of the
GAC system alone.
With the operation of the UV/Ox unit at full lamp capacity, the electrical usage has been
approximately 95,000 kilowatt hours per year and the number of GAC unit filter changes
(changeouts) have been approximately four per year. By converting to the GAC system alone,
none of the electrical usage for the UV/Ox system would be needed and approximately eight
carbon changeouts would be needed for the GAC system per year. Annual operating costs are
expected to decrease from approximately $48,500 to $18,500.
With the use of GAC filters alone, the cleanup levels for contaminants will remain the
same. Furthermore, there are no contaminants destroyed by the UV/Ox unit that cannot be
captured by the GAC filters as well. Use of the GAC filters alone was an alternative remedy
discussed in the OU-2 ROD. However, use of the UV/Ox system was selected because the
UV/Ox system was expected to operate at a higher level of efficiency and destroyed the organic
compounds on-site rather than capturing the contaminants in the GAC filters for future off-site
-------
destruction. In the OU-2 ROD, the GAC system was determined to achieve all objectives of the
selected remedy in an identical manner to the UV/Ox system, including ARARs (discharge
limits) and timing. Considerations such as storage and use of hazardous materials and high
energy use of the UV/Ox unit was not considered significant in the OU-2 ROD evaluation of the
remedies.
IV. Support Agency Comments
EPA contacted DTSC and RWQCB to discuss the proposed ESD prior to distribution of
the draft. Neither agency expressed concern with the proposed change to the selected remedy as
presented in the ESD. Both agencies were sent draft copies of the ESD for comment in February
1998 and concurred with the ESD as described above. This proposed ESD does not affect either
the completion of the remedy or the protectiveness of the selected remedy for the site as
discussed in the ROD.
V. Affirmation of the Statutory Determinations
It is the determination of EPA and the State of California that this modified remedy
continues to satisfy the statutory requirements of cleanup under the Superfund process.
Considering the information that has been developed during implementation of the remedy and
the proposed changes to the selected remedy, EPA and the State of California believe that
proposed change to the selected remedy will remain protective of human health and the
environment, will comply with Federal and State requirements that are applicable or relevant and
appropriate to this remedial action, and will be cost effective. In addition, the revised remedy
will continue to utilize cleanup solutions for the Site to the maximum extent practicable and will
utilize a technology that consumes significantly less energy.
VI. Availability of Administrative Record
The Administrative Record for this Site is available for review and comment by any
member of the public at the location mentioned above. No public meetings aire proposed for this
ESD unless public interest indicates that one may be warranted.
-------
DECLARATION
The selected remedy is protective of human health and the environment, attains Federal
and State requirements that are applicable or relevant and appropriate to the remedial action, and
is cost effective. This remedy satisfies the statuatory preference for remedies that reduce toxicity,
mobility, and/or volume as a principal element. It also utilizes permanent solutions to the
maximum extent practicable.
Date! * A,Keith T^31^ Director^/
/Superfund Division
U.S. EPA, Region 9
-------
ADMINISTRATIVE RECORD INDEX
KOHLER COMPANY LANDFILL
For the
EXPLANATION OF SIGNIFICANT DIFFERENCES (ESD)
September 1998
Date Document Description Author
3/9/98 Construction Documentation Report Kohler 33+Apps.
8/29/95 Closure Plan Approval WDNR 11
7/10/96 Plan Modification Approval WDNR 19
------- |