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Remediation Technologies Screening Matrix, Version 4.0 4.37 Thermal Treatment
(In Situ GW Remediation Technology)
  Description Synonyms Applicability Limitations Site Information Points of Contact
Data Needs Performance Cost References Vendor Info. Health & Safety
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Technology>>Ground Water, Surface Water, and Leachate

>>3.10 In Situ Physical/Chemical Treatment

      >>4.37 Thermal Treatment
Introduction>> Steam is forced into an aquifer through injection wells to vaporize volatile and semivolatile contaminants. Vaporized components rise to the unsaturated zone where they are removed by vacuum extraction and then treated.

Description:


Figure 4-37:
CrowTM Subsurface Development Process  

Steam is forced into an aquifer through injection wells to vaporize volatile and semivolatile contaminants. Vaporized components rise to the unsaturated (vadose) zone where they are removed by vacuum extraction and then treated. Hot water or steam-based techniques include Contained Recovery of Oily Waste (CROW ), Steam Injection and Vacuum Extraction (SIVE ), In Situ Steam-Enhanced Extraction (ISEE ), and Steam-Enhanced Recovery Process (SERP ). Hot water or steam flushing/stripping is a pilot-scale technology. In situ biological treatment may follow the displacement and is continued until ground water contaminants concentrations satisfy statutory requirements.

The process can be used to remove large portions of oily waste accumulations and to retard downward and lateral migration of organic contaminants. The process is applicable to shallow and deep contaminated areas, and readily available mobile equipment can be used.

Hot water/steam injection is typically short to medium duration, lasting a few weeks to several months.

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Synonyms:

Hydrous pyrolysis/oxidation; In situ steam extraction.
DSERTS Code: F15 (Hot water/steam flushting)

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Applicability:

The target contaminant groups for hot water or steam flushing/stripping are SVOCs and fuels. VOCs also can be treated by this technology, but there are more cost-effective processes for sites contaminated with VOCs.

This technology can be applied at manufactured gas plants, wood-treating sites, petroleum-refining facilities, and other sites with soils containing light to dense organic liquids, such as coal tars, pentachlorophenol solutions, creosote, and petroleum by-products.

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Limitations:

Factors that may limit the applicability and effectiveness of the process include:
  • Soil type, contaminant characteristics and concentrations, geology, and hydrogeology which will significantly impact process effectiveness.

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Data Needs:

A detailed discussion of these data elements is provided in Subsection 2.2.2. (Data Requirements for Ground Water, Surface Water, and Leachate).

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Performance Data:

Four vendors are promoting hot water or steam flushing/stripping processes. The CROW technology was tested both at the laboratory and pilot-scale under the EPA SITE Emerging Technology Program. The program showed the effectiveness of the hot-water displacement and displayed the benefits from the inclusion of chemicals with the hot water.

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Cost:

The most significant factor affecting cost is the time of treatment or treatment rate. With the mobile system, treatment rate is influenced primarily by the soil type, waste type, and on-line efficiency. Cost estimates for this technology are strongly dependent on the treatment rate and range. On average, the cost ranges from $100 to $300 per cubic yard based on a 70 percent on-line efficiency.

In stationary in situ systems, the most significant factor influencing cost is the number of wells required per unit area, which is related to the depth of contamination, permeability and site geology. Shallow contamination requires lower operating pressures to prevent soil fracturing and closer well placement. Deeper contamination requires higher operating pressures and greater well spacing; therefore, depending on the site geology, fewer wells can be used, which will lower capital costs. Cost estimates for this technology range from about $50 to $300 per cubic yard, depending on the site characteristics.  A recent study of six phase heating yielded a unit cost of $32 per cubic yard.

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References:

Treatment Technologies for Site Cleanup: Annual Status Report (ASR), Tenth Edition, EPA 542-R-01-004

Innovative Remediation Technologies:  Field Scale Demonstration Project in North America, 2nd Edition

Treatment Experiences at RCRA Corrective Actions, December 2000, EPA 542-F-00-020

Abstracts of Remediation Case Studies, Volume 4,  June, 2000, EPA 542-R-00-006

Guide to Documenting and Managing Cost and Performance Information for Remediation Projects - Revised Version, October, 1998, EPA 542-B-98-007

California Base Closure Environmental Committee (CBCEC), 1994. Treatment Technologies Applications Matrix for Base Closure Activities, Revision 1, Technology Matching Process Action Team, November, 1994.

EPA, 1990. Toxic Treatments In Situ Steam/Hot Air Stripping Technology, Applications Analysis Report, Prepared by Science Applications International Corporation, San Diego, CA, for EPA RREL, Cincinnati, OH.

EPA, 1991. In Situ Steam Extraction Treatment, Engineering Bulletin, OERR, Washington, DC, EPA Report EPA/540/2-91/005.

EPA, 1992. The Superfund Innovative Technology Evaluation Program: Technology Profiles (Fifth Edition), OSWER, EPA/940/R-92/077.

EPA, 1994. In-Situ Steam Enhanced Recovery System Hughes Environmental Systems, Inc., Demonstration Bulletin EPA/540/MR-94/510.

EPA, 1997. How Heat Can Enhance In situ Soil and Aquifer Remediation, EPA/540/S-97/502.

EPA, 1997. Steam Injection for Soil and Aquifer Remediation, EPA/540/S-97/505.

Federal Remediation Technologies Roundtable, 1995. Remediation Case Studies: Groundwater Treatment, Federal Remediation Technologies Roundtable, EPA/542/R-95/003.

Federal Remediation Technologies Roundtable, 1998. Remediation Case Studies: In Situ Soil Treatment Technologies (Soil Vapor Extraction, Thermal Processes), EPA/542/R-98/012

Federal Remediation Technologies Roundtable, 1998. Remediation Case Studies: Innovative Groundwater Treatment Technologies, EPA/542/R-98/015.

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Site Information:

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Points of Contact:

General FRTR Agency Contacts

Technology Specific Web Site:

Government Web Sites

Non Government Web Sites

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Vendor Information:

A list of vendors offering In Situ Physical/Chemical Water Treatment is available from EPA REACH IT which combines information from three established EPA databases, the Vendor Information System for Innovative Treatment Technologies (VISITT), the Vendor Field Analytical and Characterization Technologies System (Vendor FACTS), and the Innovative Treatment Technologies (ITT), to give users access to comprehensive information about treatment and characterization technologies and their applications.

Government Disclaimer

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Health and Safety:

Hazard Analysis

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