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 Dr. Trexler and our senior staff have designed,
installed, and operated ground water remediation
systems including air sparge systems; pump and treat
systems with granular activated carbon, air strippers
or ion exchange units; dual-phase extraction methods;
injection of oxidants and biological enhancers for
in-situ remediation; and natural attenuation.
Duncklee & Dunham has developed corrective action
plans using underground injection of chemicals to
oxidize VOCs or carbon sources to enhance the
biological breakdown of the VOCs. Chemicals such as
steam or base catalyzed sodium persulfate, hydrogen
peroxide, Fenton's Reagent, potassium and sodium
permanganate, and slow release oxygen compounds are
used to oxidize and/or biodegrade the organic
compound. The biological process of anaerobic
reductive dechlorination can be enhanced by the
addition of carbon sources such as lactate or
emulsified vegetable oils.
Mr. Dunham has permitting and is currently managing
the remediation of a ground water plume site in
Delaware contaminated by methyl tertiary butyl ether (MTBE)
and other oxygenates found in gasoline by injecting
sodium persulfate and steam. In Virginia, Mr. Dunham
has also designed and permitted an injection program
to enhance the indigenous microorganisms and increase
their breakdown of dissolved nitrate contamination.
Dr. Trexler has designed and permitted an underground
injection program for a North Carolina site using
hydrogen peroxide and persulfate to remediate two
landfill trenches containing chlorinated VOCs. The
two trenches represent the source area for a
1,000-foot long plume contaminated by PCE,
trichloroethene, and the dichloroethenes. Underground
injection is also being used in the contaminated plume
to enhance the ongoing reductive dechlorination
process.
Mr. Duncklee currently has permitted and is operating:
·
a chemical oxidation process for removing
tetrachloroethene (PCE) from ground water using
potassium permanganate at a site in Asheboro, North
Carolina,
·
a petroleum contaminated site using slow release
oxygen compounds in Rowan County, North Carolina,
·
the use of base catalyzed persulfate to remediate a
dissolved gasoline ground water plume at a site in
Raleigh, North Carolina, and
·
a chemical oxidation process for removing dissolved
chloroform using steam catalyzed sodium persulfate for
a project in Rabun, Georgia. (see
images below)
Mr. Duncklee is a past member of Interstate Technology
& Regulatory Council (ITRC), In-Situ Chemical
Oxidation (ISCO) team. The ITRC promotes innovative
technologies. The ISCO team promotes the use of
chemical oxidizers and helps establish standard
procedures for using chemical oxidizers effectively
and safely.
Our staff has obtained numerous agency approvals for
natural attenuation soil and ground water corrective
action plans (CAPs). Natural or passive attenuation
CAP rules are most suitable where concentrations of
contaminants in ground water are moderate to low or
where there is moderate to low exposure to sensitive
receptors. For petroleum UST sites, regulations
typically require the removal of free product, and
then the State program sets the cleanup level for the
dissolved constituents.
The passive
CAP includes the removal of the primary source
of the release (a leaking UST for example).
Next, secondary sources such as contaminated soils are
controlled by removal, soil vapor extraction, or other
methods. A ground water monitoring well network
is installed and sampled to monitor the compounds of
concern over time. The natural processes of
biodegradation and natural attenuation will reduce
levels of petroleum hydrocarbons as well as
chlorinated solvents under the proper conditions.
Mr. Duncklee has obtained EPA Region 4 approval of
monitored natural attenuation for a CERCLA regulated
site in eastern North Carolina with a chlorinated
solvent plume. Having received EPA and NC DENR
approval of the Remedial Design/Remedial Action work
plan in early 2000, this project is currently in the
monitoring phase.
In North Carolina, the senior staff is involved with
sites under the passive CAP regulations. In 1996, Mr.
Duncklee obtained what is believed to have been only
the second DENR approval of a 106 (l) CAP for a site
with ground water impacted with chlorinated
hydrocarbons.
Persulfate Injection Pilot Test
Chloroform Ground Water Plume
Georgia Site
IMAGES TO THE RIGHT ARE THE CROSS
SECTION VIEWS OF THE IMAGES ON THE LEFT.
CLICK ON AN IMAGE FOR A LARGER VIEW.
Pre Injection
Six Months Post Injection
Eighteen Months Post Injection
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