United States Department of the Interior

NATIONAL PARK SERVICE

 INTERMOUNTAIN REGION

 12795 West Alameda Parkway

 Post Office Box 25287

 Denver, Colorado  80225-0287

INNOVATIVE SITE CHARACTERIZATION AND REMEDIATION

A Partnership between the National Park Service, Michael Baker Jr., Inc., and H&H Eco Systems, Inc.

May 2003

ABSTRACT:

The National Park Service Intermountain Regional Support Office, Denver (NPS-IMDE) has formed a partnership with Michael Baker Jr., Inc. (Baker) with the goal of cost effectively characterizing, delineating, and remediation contaminated sites within the parks of the Intermountain Region.  To meet these goals, the partnership is utilizing innovative analytical and remedial technologies.  Two separate sites were chosen with broad application to other DOI agencies/sites.  The first site consists of lead based paint (LBP) soil contamination, and the second site has high levels of diesel-contaminated soil.

The LBP soil contamination site is located at Fort Laramie National Historic Site in Wyoming.  The soil became contaminated during the restoration of a historic building, when the structure's exterior was cleaned multiple times to remove old "lead bearing" paint.  NPS-IMDE, in partnership with Baker, developed a plan to determine the nature and extent of lead contamination in both surface and subsurface soils using field analytical methods to provide "real time" contaminant detection.  A portable lab using the highly accurate Palintest SA-500 Scanning Analyzer was used to determine quantitative soil lead concentrations (in the field) by following an approved sampling protocol.  Samples were collected on a systematic grid around the building to more accurately determine locations/areas of lead contamination requiring remedial measures.  This type of field sampling/analysis proved to be accurate, both in cost and time efficiency.  An average of 30 samples were collected per day with an average cost for field analytical supplies of $9.00 per sample; including labor, the total cost for field analysis was $16.00 per sample.  For comparison, the laboratory analytical cost for lead in a soil sample is $25.00 per sample (this does not include labor costs for collection and shipping or validation).  A percentage of the field screening samples were submitted as confirmatory samples to a Wyoming state certified lab for lead analysis using USEPA methods and protocols.  Confirmatory samples were selected from detect and non-detect field results.  An independent third party validation subcontractor performed validation of the laboratory results.  The field and laboratory data was then used to design a remediation plan for the site.

Advantages of the accurate-real time field sampling:

  • It eliminates sample packing and shipping time, as well as associated supplies;
  • It eliminates broken sample bottles which often require re-sampling
  • It eliminates additional sampling often necessary with unidentified “hot spots”
  • It allows the field team to make real-time adjustments and focus on the exact area of contamination, which makes the field program dynamic and much more effective
  • Real-time data provides the necessary information to determine decontamination and site control measures
  • It allows planning and report writing prior to receiving data packages from the laboratory.

The diesel-contaminated former UST site is located in southern Utah at Hall's Crossing in Glen Canyon, National Recreation Area.  Soil contamination resulted from the release of diesel fuel from leaking transmission lines for the underground storage tanks. Initial average TPH (DRO) soil levels from composite samples were 960 parts per million (ppm).  A highly efficient, ex-situ, bioremediation treatment technology was selected to clean the contaminated soil. 

The contaminated soil was excavated and placed into an elongated pile or soil windrow. Samples were collected to assess the level of contamination in the soil before treatment and every 2-3 weeks thereafter.  The soil was treated with multiple amendments and thoroughly mixed.  Proper soil moisture content was maintained through addition of water during periodic mixing treatments.  Periodic mixing is required to help off-gas accumulated bioremediation byproducts, such as carbon dioxide; and to replenish oxygen, which is required for this aerobic biological process.  Tarpaulins covered the windrow between treatment events to protect the soil from desiccation and to prevent rainwater from creating contaminated runoff.  At the end of the treatment, samples were collected and analyzed.  Diesel range hydrocarbon compounds were remediated from this soil to a level below the State of Utah’s Recommended Cleanup Level (RCL) of 100 ppm.

This new proprietary technology uses a patented "Microenfractionation®" process to optimize the biological degradation of chemical contaminants within the soil. 

This process works by providing the optimal conditions for indigenous microorganisms that are present in the soil (primarily aerobic and sometimes anaerobic bacteria and fungi), to increase their metabolic rate and grow and multiply and, in turn, consume hydrocarbon contaminants.  In this process, the contaminated soil is microenfractionated, hydrated, and supplemented with oxygen and select nutrients including trace minerals to promote optimum biological growth of these beneficial organisms.  The process has numerous advantages over other remediation technologies:

  • Once treated, the soil can be backfilled into the original excavation eliminating the need to transport the soil offsite;
  • It does not introduce foreign organisms/bacteria;
  • It is effective even in colder climates
  • It is cost effective
  • It is very time effective
     
  • The enhanced agronomic condition of the remediated soil provides superior conditions for vegetation growth and reuse on-site.
  • As the contaminants degrade, microorganism levels reduce back to normal levels
  • Bi-products are natural and nontoxic.

This Microenfractionation® and soil enhancement process eliminates the use of time-consuming, dangerous, and expensive chemicals, and it is well suited for most hydrocarbon and PCB contaminated sites.  The key to this technology relies on the Microenfractionator® to break up any hot spots of contamination within the soil matrix and to expose all soil particles to any added amendments.