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Remediation Technologies Screening Matrix, Version 4.0 4.36 Dual Phase Extraction
(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

      >>4.36 Dual Phase Extraction
Introduction>> A high vacuum system is applied to simultaneously remove various combinations of contaminated ground water, separate-phase petroleum product, and hydrocarbon vapor from the subsurface.

Description:

Figure 4-36:
Typical Dual Phase Extraction Schematic  

Dual-phase extraction (DPE), also known as multi-phase extraction, vacuum-enhanced extraction, or sometimes bioslurping, is a technology that uses a high vacuum system to remove various combinations of contaminated ground water, separate-phase petroleum product, and hydrocarbon vapor from the subsurface. Extracted liquids and vapor are treated and collected for disposal, or re-injected to the subsurface (where permissible under applicable state laws).

In DPE systems for liquid/vapor treatment, a high vacuum system is utilized to remove liquid and gas from low permeability or heterogeneous formations. The vacuum extraction well includes a screened section in the zone of contaminated soils and ground water. It removes contaminants from above and below the water table. The system lowers the water table around the well, exposing more of the formation. Contaminants in the newly exposed vadose zone are then accessible to vapor extraction. Once above ground, the extracted vapors or liquid-phase organics and ground water are separated and treated. DPE for liquid/vapor treatment is generally combined with bioremediation, air sparging, or bioventing when the target contaminants include long-chained hydrocarbons. Use of dual phase extraction with these technologies can shorten the cleanup time at a site. It also can be used with pump-and-treat technologies to recover ground water in higher-yielding aquifers.

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Synonyms:

Multi-phase extraction; Vacuum-enhanced extraction; Free product recovery; Liquid-Liquid Extraction.
DSERTS Code:

(Dual-phase extraction)
F13 (Free product recovery)
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Applicability:

The target contaminant groups for dual phase extraction are VOCs and fuels (e.g., LNAPLs). Dual phase vacuum extraction is more effective than SVE for heterogeneous clays and fine sands. However, it is not recommended for lower permeability formations due to the potential to leave isolated lenses of undissolved product in the formation.

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Limitations:

Factors that may limit the applicability and effectiveness of the process include:
  • Site geology and contaminant characteristics/distribution.
  • Combination with complementary technologies (e.g., pump-and-treat) may be required to recover ground water from high yielding aquifers.
  • Dual phase extraction requires both water treatment and vapor treatment.

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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).

Data needs include physical and chemical properties of the product released (e.g., viscosity, density, composition, depth, and solubility in water); soil properties (e.g., capillary forces, effective porosity, moisture content, organic content, hydraulic conductivity, and texture); nature of the release (e.g., initial date of occurrence, duration, volume, and rate); geology (e.g., stratigraphy that promotes trapped pockets of free product); hydrogeologic regime (e.g., permeability, depth to water table, ground water flow direction, and gradient); and anticipated product recharge rate.

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Performance Data:

Once contaminants are detected, the immediate response should include both removal of the source and recovery of product by the most expedient means. Dual Phase Extraction methods will extract contaminated water with the product. It may be necessary to separate water and product prior to disposal or recycling of the product. As a result of the removal of substantial quantities of water during dual pumping operations, on-site water treatment will normally be required. When treatment of recovered water is required, permits will usually be necessary.

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Cost:

This cost estimate is does not include the costs for additional treatment steps which may be necessary when employing dual phase extraction technology such as the treatment and disposal of process residuals.  The key cost driver information and cost analysis was developed using the 2006 version of the Remedial Action Cost Engineering and Requirements (RACER) software. 

Key Cost Drivers 

·        Soil Type

o       Soil type determines permeability, which is the primary cost driver.  Dual phase extraction works best for permeable sand-silt mixtures.  Impermeable (clayey) or excessively permeable (gravel/sand) soils are more recalcitrant.

·        Depth to Base of Contamination

o       Depth to the base of contamination is the secondary driver, as an increased thickness and depth of contaminated groundwater increases cost.

Cost Analysis

The following table represents estimated costs (by common unit of measure) to apply dual phase extraction technology at sites of varying size and complexity.   A more detailed cost estimate table which includes specific site characteristics and significant cost elements that contributed to the final costs can be viewed by clicking on the link below.

GW TECHNOLOGY:

Dual Phase Extraction

 

RACER PARAMETERS

Scenario A

Scenario B

Scenario C

Scenario D

Small Site

Large Site

Easy

Difficult

Easy

Difficult

 

 

 

 

 

CUBIC YARDS PROCESSED

12,100

12,100

24,200

24,200

COST PER CUBIC YARD

$25

$55

$23

$52

COST PER 1000 CUBIC YARDS

$25,462

$54,545

$23,460

$52,381

Detailed Cost Estimate

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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

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

American Petroleum Institute, 1989. A Guide to the Assessment and Remediation of Underground Petroleum Releases, Publication 1628, API, Washington, DC, 81 pp.

MTBE Treatment Case Studies presented by the USEPA Office of Underground Storage Tanks.

DOE, 1994. Technology Application Analysis: Petroleum Product Recovery and Contaminated Groundwater Remediation Amoco Petroleum Pipeline Constantine, MI, prepared by Stone & Webster Environmental Technology & Services.

DOE, 1994. Technology Application Analysis: Recovery of Free Petroleum ProductFort Drum, Fuel Dispensing Area 1595 Watertown, New York, prepared by Stone & Webster Environmental Technology & Services.

EPA, 1988. Cleanup of Releases from Petroleum USTs: Selected Technologies, Washington, DC, EPA/530/UST-88/001.

EPA, 1997. Analysis of Selected Enhancements for Soil Vapor Extraction, EPA OSWER, EPA/542/R-97/007.

FRTR, 1998. Remediation Case Studies: Six Phase Soil Heating at the U.S. Department of Energy's Savannah River Site, M Area, Aiken, South Carolina; and Hanford Site, 300-Area, Richland, Washington.

Kram, M.L., 1990. "Measurement of Floating Petroleum Product Thickness and Determination of Hydrostatic Head in Monitoring Wells", NEESA Energy and Environmental News Information Bulletin No. 1B-107.

Kram, M.L., 1993. "Free Product Recovery: Mobility Limitations and Improved Approaches", NFESC Information Bulletin No. IB-123.

NEESA, 1992. Immediate Response to Free Product Discovery, NEESA Document No. 20.2-051.4.

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Site Information:

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Points of Contact:

General FRTR Agency Contacts

Technology Specific Web Sites:

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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Introduction Contaminants Treatments/Profiles References Appendices Navigation