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BIOTROL, INC.
(Soil Washing System)

This vendor is participating in the EPA Superfund Innovative 
Technology Evaluation (SITE) Program.  The following technology 
profile has been reproduced from the SITE Technology Profile 
document, 7th edition.  The SITE profile has been supplemented by 
MVA Consulting Inc. using information obtained from the vendor or 
from other SITE publications, referenced at the end of this file. 

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TECHNOLOGY DESCRIPTION:

The BioTrol Soil Washing System is a patented, water-based volume
reduction process used to treat excavated soil.  The system may
be applied to contaminants concentrated in the fine-size soil
fraction (silt, clay, and soil organic matter) or  contamination
associated with the coarse (sand and gravel) soil fraction.

As a part of the process, debris is removed from the soil, and
the soil is mixed with water and subjected to various unit
operations common to the mineral processing industry.  These
operations can include mixing trammels, pug mills, vibrating
screens, froth flotation cells, attrition scrubbing machines,
hydrocyclones, screw classifiers, and various dewatering
operations (see figure below).

The core of the process is a multistage, countercurrent,
intensive scrubbing circuit with inter-stage classification.  The
scrubbing action disintegrates soil aggregates, freeing
contaminated fine particles from the coarser material.  In
addition, surficial contamination is removed from the coarse
fraction by the abrasive scouring action of the particles
themselves.  Contaminants may also be solubilized, as dictated by
solubility characteristics or partition coefficients.

Contaminated residual products can be treated by other methods. 
Process water is normally recycled after biological or physical
treatment.  Contaminated fines may be disposed of off site,
incinerated, stabilized, and biologically treated.

WASTE APPLICABILITY:

This system was initially developed to clean soils contaminated
with wood preserving wastes, such as polynuclear aromatic
hydrocarbons (PAH) and pentachlorophenol (PCP).  The system may
also apply to soils contaminated with petroleum hydrocarbons,
pesticides, polychlorinated biphenyls (PCB), various industrial
chemicals, and metals.

STATUS:

The soil washing system was demonstrated under the SITE Program
between September and October 1989 at the MacGillis and Gibbs
Superfund site in New Brighton, Minnesota.  A pilot-scale unit
with a treatment capacity of 500 pounds per hour operated 24
hours per day during the demonstration.  Feed for the first phase
of the demonstration (2 days) consisted of soil contaminated with
130 parts per million (ppm) PCP and 247 ppm total PAHs; feed for
the second phase (7 days) consisted of soil con-taining 680 ppm
PCP and 404 ppm total PAHs.

Contaminated soil washing process water was treated biologically
in a fixed-film reactor and recycled.  A portion of the
contaminated soil washing fines was treated biologically in a
three-stage, pilot-scale EIMCO Biolift  reactor system supplied
by the EIMCO Process Equipment Company.

The Applications Analysis Report  (EPA/540/A5-91/003) has been
published.  The Technology Evaluation Report is available from
National Technical Information Service (Volume I Order No. 
PB92-115 310 VI, Volume II Order No. PB92-115 328-V2-PtA, and
PB92-115
336-V2-PtB).

DEMONSTRATION RESULTS:

Key findings from the BioTrol demonstration are summarized below:

>  Feed soil (dry weight basis) was successfully separated into
   83 percent washed soil, 10 percent woody residues, and 7
   percent fines.  The washed soil retained about 10 percent of
   the feed soil contamination; 90 percent of this contamination
   was contained within the woody residues, fines, and process
   wastes.

>  The soil washer removed up to 89 percent PCP and 88 percent
   total PAHs, based on the difference between concentration
   levels in the contaminated (wet) feed soil and the washed
   soil.

>  The system degraded up to 94 percent PCP in the process water
   during soil washing.  PAH removal could not be determined
   because of low influent concentrations.

>  Cost of a commercial-scale soil washing system, assuming use
   of all three technologies, was estimated to be $168 per ton. 
   Incineration of woody material accounts for 76 percent of the
   cost.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Mary Stinson
U.S. EPA
Risk Reduction Engineering Laboratory
Building 10, MS-104
2890 Woodbridge Avenue
Edison, NJ  08837-3679
908-321-6683
Fax: 908-321-6640

TECHNOLOGY DEVELOPER CONTACT:
Sandra Clifford
BioTrol, Inc.
10300 Valley View Road, Suite 107
Eden Prairie, MN  55344-3456
612-942-8032
Fax: 612-942-8526
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Sources of information in this profile:

EPA Superfund Innovative Technology Evaluation Program 
        Technology Profiles Seventh Edition, November 1994. 
        EPA/540/R-94/526.

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