In-Situ Remediation through Steam Injection and Extraction

Soil vapor extraction (SVE) is an in situ remedial technology that is used to remove volatile organic contaminants from soil. Air is drawn through the subsurface by applying a vacuum to extraction points, from which the vapor phase of the volatile contaminants is removed. The soil vapors (off-gases) from the system are collected and treated by passing over granular activated carbon(GAC). Groundwater is separated and treated through the use of separator tanks and carbon filtration, then re-injected. SVE increases the effectiveness of naturally occurring micro-organisms, thereby enhancing bio-remediation of contaminated sites. 

GWS Environmental Contractors augments traditional Soil Vapor Extraction by adding Steam injection to the process.  Steam injection helps to pressurize, heat and volotolize sub-surface contaminants, thereby increasing the speed and efficacy of traditional SVE.  Steam SVE works well on contaminants including Number 2 – 4 oils, LNAPLs such as TCE, PCE and other pollutants. GWS Environmental Contractors Inc. has many years experience in designing, implementing and managing Steam Injection SVE systems on commercial and residential sites.

If you would like more information on how In-Situ Steam Injection SVE could save money and time on your next remediation job, please contact GWS Environmental Contractors to find out more.

  • Increased Vapor Pressure
  • Quicker Mobilization of   Contaminants
  • Use On A Wide Range of Contaminants
  • Increased Microbial Activity Contributes to Ongoing Remediation
  • Excellent in deep sandy soils
  • Quicker remediation than Chemical Injection more than 2/1 time frame
  • Less long term costs in Testing vs. Chemical Injection

 

Case Studies


Steam Injection - Soil Vapor Extraction Project Case Study – Thorne


History:
An existing UST was in close proximity to a residential structure.  Customers did not want to excavate and soil makeup was not conducive to excavation.

Contaminants:
No. 2 heating oil leaking for many years
Plume depth at 18 feet
Plume migrated under house foundation

Site Constraints:
Customer didn’t want digging on the property
Depth of Contamination
Sandy Soils

Response:
7 Galvanized Steel Injection points installed 20’ BG.  2 installed at 35 degrees angle under house
4 Galvanized Steel Extraction Points installed 20’ BG
4 Month Remediation Time

Steam Injection – Soil Vapor Extraction Project Case Study – Gooding


History:
A UST in close proximity to a residential structure
No. 2 heating oil leaking for many years
Groundwater was affected

Site Constraints:
Sandy Soils/Loose soil structure
Plume depth at 23 feet BG
Plume migrated under house foundation and into GW

Response:
7 1-1/2” Galvanized Steel Injection points 2 installed at 35 degrees to get under house
4 2” Galvanized Steel Extraction Points
5 Month Remediation Time
20’ Re-Injection Trench

SVE

Did you know:

  • Can save money over Ex-Situ methods
  • Can be an excellent alternative to other In-Situ remediation methods
  • Mobilizes number 2 heating oil by volatilizing the free product so it can be extracted through vacuum points.
  • Enhances subsurface permeability and increases a treatment agent's radius of influence.
  • Does not threaten the structural integrity of foundations, or buried utilities.
  • Allows you to remediate to greater depths than ex-situ normally does
  • Because in situ technologies require no excavation, risk from exposure to contaminated media is reduced, compared with levels of risk associated with ex situ technologies that require excavation.
  • Enhances natural bio-remediation by activating micro-organisms for enhanced bio-remediation

Soil vapor extraction (SVE) is an in situ remedial technology that is used to remove volatile organic contaminants from soil. Air is drawn through the subsurface by applying a vacuum to one or more extraction points, from which the vapor phase of the volatile contaminants is removed. The soil vapors (off-gases) from the system are collected and generally treated by one or more technologies, such as granular activated carbon(GAC), SVE often is used with other technologies such, as air sparging, to enhance the removal of biodegradable contaminants or to strip volatile contaminants from the saturated zone, respectively.

SVE increases the effectiveness of naturally occurring micro-organisms, thereby enhancing bio-remediation.  Inoculums (e.g., nutrient solutions or engineered microorganisms) can also be used to remediate subsurface contaminants. The subsurface transport of these inoculums can be greatly enhanced by releasing them into gas streams and creating an atomized mist. 

Reference:

Find out more about In-Situ SVE at:
http://www.frtr.gov/matrix2/section4/4-7.html
http://clu-in.org/download/remed/asr/12/asr12_main_body.pdf