BIO REM^® USA, INC.

"Soil & Water Decontamination Specialists"

ENVIRONMENTAL PRODUCTS & SERVICES

Site Description:

    Carousel Cleaners is an active retail dry cleaner.  The site topography and gradient are relatively flat.  Several residences and commercial businesses are located within the immediate vicinity of the site.  The site is bounded by an apartment complex to the east, a vacant lot to the north, and a small business park to the south.

    Contamination originating from surface spills near the dry cleaning machine and adjacent vacant lot has entered the surface and subsurface soils and has migrated through the subsurface via groundwater.  Soil has been impacted by PCE contamination in the vicinity of the dry-cleaner building.  The greatest identified soil contamination was located outside the building, adjacent to the north access door to the dry-cleaning machine.  Elevated levels of 1,2,4-trimethylbenzene (TMB) were also detected in the sample collected adjacent to the north access door by the dry-cleaning machine.  PCE appears to be the dominant contaminate in soil outside the building footprint.

Geology and Hydrogeology:

    Soil beneath the site consists of Pleistocene lacustrine and fluvial unconsolidated clay, silt, and sand approximately 30 to 35 feet thick.  The unconsolidated soil is underlain by Pleistocene and Pliocene andesite flow basalt and flow breccia, which include Boring Lava.

    The shallow aquifer beneath the site is composed of native silt, clay, and sand.  Groundwater data from existing wells in the area suggest water in the shallow aquifer varies in thickness from approximately 12 to 20 feet, depending on the time of the year.  Depth to shallow groundwater ranges from 9 to 11 feet below ground surface (BGS) in the winter and spring months to 19 to 21 feet BGS in late summer and early fall.  Shallow groundwater flow direction in the area has been estimated to be toward the southeast.

    Based on the well log from the deep well (DW-1) located on site, a deep aquifer is present beneath the site.  The deep aquifer consists of a unit of fine-grained sand from 131 to 164 feet BGS.  A confining unit of yellow-brown sandstone is encountered at 175 feet BGS.

Scope of Project:

    Bio Rem's H-10™ product was chosen to remediate the compounds of this site.  The application methods, monitoring, and all other directions needed were communicated to Hart Crowser, the on site operational engineers and consultants under the supervision of the Department of Environmental Quality (DEQ) for Carousel's Dry Cleaners Site in order for them to do the project themselves with the use of Bio Rem's H-10™ and support.

    With more porous soils, the Bio Rem solution is normally applied through a matrix of borings.  The initial horizontal spread is a 3 to 5 feet radius around each boring.  However, given the low porosity of this soil due to the clay content, trenching will be required to apply the product at this site.  It is critical that the bacterial solution be placed in contact with the food source as soon as possible after propagation process.

    Once they have properly completed all necessary applications they will next have to monitor the site.  In order to properly monitor this program, we not only need to track the degradation of PCE, but also the breakdown compounds (TCE, DCE, Vinyl Chloride).  It is anticipated that these daughter compounds will increase as the PCE degrades.  Water and soil should be taken in the same general vicinity of MW-4/GP-13 every 30 days.

     In addition to monitoring the contaminates, total Heterotrophic bacteria (plate count) should be run on the groundwater, as well as Chlorides, pH, Dissolved Oxygen, and nitrogen concentrations.  These tests will track the progress of the bacteria.  However, once the bacteria are in the contaminant plume, there are no additional sources of oxygen or nutrients required for the H-10 to completely biodegrade the contaminants.

Summary of Pilot Study:

    A bioremediation pilot study is being conducted at the Carousel site in Oregon City, Oregon to enhance biodegradation of PCE in subsurface soil and groundwater.  The study was initiated in March 2002 and includes the application of a bacteria mixture to monitoring wells and a subsurface system of PVC screen and piping along with monthly groundwater monitoring.  A second application of the bacteria mixture, H-10™, was applied in October 2002.  Monthly groundwater monitoring was conducted from March through September 2002.

    During the period of March 2002 to September 2002, PCE levels decreased by approximately 90 percent in groundwater sampled from MW-1, MW-4, and the injection well.  Based on analytical results and a comparison of baseline data, the application of the H-10™ bacterium mixture has significantly decreased PCE concentrations in shallow groundwater beneath the site.

    Recent analytical results from sampling conducted in September 200 indicate that the PCE levels have stabilized (i.e. levels are no longer decreasing) and heterotrophic plate counts have steadily decreased since May 2002.

    Evaluation of the effectiveness of the H-10™ bacterium indicates that PCE contamination has been reduced and can be directly correlated to the bacterium injection.  The project is a work in progress and is currently being monitored in order to track final results.

Maps

Lab Result Graphs