Organoclay Sediment Cap at Superfund Site
The
McCormick and Baxter organoclay sediment
cap project area covers approximately 58 acres of terrestrial and
aquatic land located on the east bank of the Willamette River in Portland,
Oregon. The organoclay sediment cap itself will be placed over the site
of the former McCormick & Baxter company, which was founded in the
early 1940s to produce a variety of treated wood products during World
War II. Various wood treatment processes have been used at the facility,
and site investigations between 1983 and 1990 revealed many releases of
chemical compounds such as pentachlorophenol (PCP), creosote, chromium
and arsenic to soil, groundwater, and sediment. In 1990, the wood treatment
operations ceased and early remediation actions were initiated to remove
process equipment, piping tanks, and treatment formulations. The organoclay
sediment cap is part of an ongoing process to remediate the site, which
is presently listed as a Superfund site under the Comprehensive Environmental
Response, Compensation, and Liability Act (CERCLA).
Over the past several years, a number of inspections, investigations,
and remedial actions have been performed at the site. Most notably, in
2003 Remtech Inc. completed work on a subsurface barrier wall surrounding
the primary waste areas within the upland portion of the 43-acre property.
Chronology
In
July of 2004, The contractor for the project, Remtech
Inc, began work this phase of the McCormick and Baxter project. The
project is part of the effort to cleanup the superfund site and the adjacent
shore and bed of the Willamette River. Consisting of site cleanup and
the installation of articulated concrete block over a layer of ET-1 Activated
Clay, this project required one of largest single applications of organophilic
clay ever implemented - over 1.2 million pounds of organophilic
clay.
Operational Evaluation
Aqua Technologies ET-1 Activated Clay plays a crucial role
in this project. Typically this type of organophilic clay is used to treat
water from oil-well-drilling operations, but the effectiveness and environmental
safety of the product initiated enough confidence to apply it for use
in the first real full scale application in an environmental project.
Easily one of the most complex and largest environmental cleanups that
the state of Oregon has ever implemented, the innovative use of ET-1 Activated
Clay will no doubt set new standards within the industry.
Current Operating Status
The
area to be capped will be approximately 25 acres in size; capped with
about 1 foot of ET-1 Activated
Clay in three separate areas covering 21 of the 25 acres. The capped
area will be armored by articulated concrete block and 6-inch minus rock.
Any existing non-aqueous phase liquid (NAPL)
migration seeps will be covered with organophyllic clay, where the material
will adsorb the contaminants tightly enough to be considered environmentally
safe. Additionally, the river banks will be upsloped with clean soil fill
and topsoil placed to support plantings, reinforced by a turf
reinforcement mat between the soil layers.
Summary
The project expects to cost approximately $12 million, and
the projects' contractor, Remtech Inc., and the project will reach completion
in October of 2004.
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