DUNCKLEE & DUNHAM


ENVIRONMENTAL CONSULTANTS

 

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Soil and Ground Water Remedial Systems

 

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. 

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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

                            


 

 
 
Latest News at Duncklee & Dunham


June 2008

Salisbury NC Site - A variance from NC 2L ground water standards has been approved by NC DENR for this project. Very few variance requests have been approved by the agency over the years. Duncklee & Dunham designed and applied for the variance request on behalf of our client for levels of benzene and naphthalene in ground water at this industrial site.

Rocky Mount, NC Site - The excavation of chromium impacted soils is underway for a local NC project. The remediation work plan includes the use of x-ray fluorescence instrumentation to obtain real time field data on metals levels in the soils.

Research Triangle Park, NC - Dr. Bryson Trexler continues to provide services to one of the world's leading pharmaceutical companies.

Colorado, Texas, and California - Daphne Olszewski is traveling this month to perform ISO audits of several major Brownfields development projects in the western US.


April 2008

Southeastern US - Tom Dunham continues to provide services to a major southeastern US agricultural cooperative. Duncklee & Dunham personnel have provided professional services to this client for almost 20 consecutive years at hundreds of project sites. Current projects range from Phase I ESAs for property transactions to a large scale ground water remediation system at an oil terminal on the Ohio River in Kentucky.


March 2008

The firm has three senior staff members certified by NC DENR as Registered Site Managers with the IHSB Registered Environmental Consultant (REC) program. Each RSM has over 20 years of individual environmental consulting experience.
 

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     Duncklee and Dunham
     511 Keisler Drive - Suite 102
     Cary, NC 27518

 

     (919)858-9898
     (919)858-9899 (FAX)
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