Bioremediation on Alaska's Kenai Peninsula:
Two Joint ETTL/BIO-FAC Projects

In the two Alaskan projects briefed below, ETTL joined together with BIO-FAC, of Kenai, Alaska, to bioremediate petroleum-contaminated soil ex-situ on premises belonging to a major oilfield technical services organization. ETTL was responsible for coordinating both projects to insure that bench scale laboratory procedures would be incorporated into the large-scale engineering design and constructions implemented by BIO-FAC, as well as providing assistance in construction design, and consultation during the projects. BIO-FAC was primarily responsible for construction of the "treatment cell" used and of the leachate recovery and reapplication system. At right, Doug Flatt, ETTL's president, looks over one end of the treatment cell before its plastic cover was added. During the course of the projects, BIO-FAC provided large-scale project design, site monitoring, regulatory liaison, and documentation of site closure. Dr. James Stewart, of UT-Tyler, was called upon to isolate and identify indigenous microbes from the contaminated soils, to supply freeze-dried microbial concentrates to the projects, and for results evaluations.

Case History 1

In 1992, ETTL joined with BIO-FAC to bioremediate 1030 cubic yards of petroleum contaminated soil on the premises of the above-mentioned oilfield technical services organization. The soil, located in Kenai, Alaska, on the Kenai Peninsula, was a homogenous fine glacial till material, averaging some 600-700 parts per million (ppm) of hydrocarbon contamination, with some portions reaching levels in the neighborhood of 6600 ppm. Remediation target levels were established at 200 ppm by the Alaska Department of Environmental Conservation (DEC). Because the Kenai area has short, moderate summers and extremely cold wintertime conditions, a swift-acting bioremediation process was called for. To ensure that biotreatment would continue despite rapidly falling temperatures at the end of the Alaskan summer, ETTL designed and BIO-FAC built a plastic-covered "bio-cell reactor" which would facilitate remediation of the soil as well as leachate and decontamination wash water. In addition, a Bio-Reactor Van was built, containing four reactor tanks for preparation of microbe-rich treatment water, further enriched with bacterial nutrients, micro-nutrients, and a biodegradable surfactant.

After preliminary evaluation, treatability studies and completion of bio-system construction, the soil to be treated was moved into the cell. Oxygenated indigenous microbes and nutrient enriched leachate were added and recycled to the system until target levels for soils and leachate had been accomplished. Treatment began on July 5, 1992. The contaminant levels had been remediated to 160 ppm (below target levels) by October 9, 1992, within the time frame set by the client and at quoted cost.

TPH data were monitored by use of supercritical fluid extraction (SFE) followed by IR evaluation. Viability of bacterial hydrocarbon degraders was measured by a modification of most probable number (MPN) procedures. Moisture, pH, oxygen and temperatures probes were installed to monitor those constituents. Initial and final data were obtained via EPA 8100 M methodology according to the Alaska DEC specifications.

Case History 2

In 1993, ETTL again joined with BIO-FAC, this time to bioremediate 1300 cubic yards of diesel-contaminated soil in Kenai, Alaska. The soil, again a homogeneous fine glacial till from the premises of the same client, averaged 900-2000 ppm of hydrocarbon contamination. The Alaska DEC set the same remediation target levels (200 ppm) as in the above Case History. Except for slight modifications to the bio-system, the same procedures and cell were used; and constituents were remediated to levels of 50 ppm within 45 days, well within the time frame set by the client and at the quoted cost. The photo at above right shows the four reactor tanks in the Bio-Reactor Van, as well as Ray Adamson, BIO-FAC's president.

For further information on these projects,
contact ETTL's Jack Holsomback

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