Mobile Dual Phase Extraction (MDPE)
EE&G's fleet of Mobile Dual Phase Extraction (MDPE) trailers delivers high-vacuum groundwater remediation across 41 states.
What is Mobile Dual Phase Extraction (MDPE)?
Mobile Dual Phase Extraction (MDPE) is a trailer-mounted groundwater remediation method that uses high vacuum to pull both contaminated groundwater and vapor from existing wells at the same time. EE&G has operated an MDPE fleet across 41 U.S. states since 1987, recovering both dissolved-phase contaminants and free product (NAPL) on petroleum and chlorinated-solvent sites.
How MDPE Works
Each EE&G MDPE deployment follows the same six-step sequence, sized to the site's wells and contaminant load.
- 1
Well selection
EE&G evaluates the existing monitoring or recovery well network (2"–6" diameter) and selects the wells positioned over the highest-impact portion of the plume.
- 2
High-vacuum extraction
The trailer-mounted system pulls simultaneous liquid and vapor from the wells under up to 28" Hg of vacuum, capturing both dissolved-phase contaminants and free product (NAPL).
- 3
Knockout chamber separation
Recovered fluid passes through a knockout chamber that separates groundwater from the vapor stream so each phase can be treated on its own dedicated train.
- 4
Water treatment or off-site disposal
Groundwater is either polished on-site through carbon and air-stripping or containerized for off-site disposal, depending on permit conditions and contaminant load.
- 5
Catalytic oxidation of vapors
Vapors are destroyed in an electric catalytic oxidizer rated for 300–600 SCFM, eliminating VOCs without the fuel, emissions, or permitting overhead of a thermal oxidizer.
- 6
Monitoring and reporting
EE&G tracks influent and effluent concentrations, mass removed, and runtime so progress can be reported to TCEQ or the controlling regulatory authority.
MDPE Advantages
Mobile units — trailer-mounted, target multiple plume areas
High vacuum — up to 28" Hg, works in most geological settings
Portable power — runs on generators, no onsite power needed
Enhanced vapor recovery — additional NAPL recovery
Assists natural attenuation
No onsite maintenance cost — all-inclusive service
No decommissioning cost — eliminates fixed system teardown
Large radius of influence
High efficiency 300–600 SCFM oxidizers
Adjustable groundwater production
Uses existing monitoring/recovery wells (2"–6" diameter)
Small footprint — as little as two parking spots, business stays open
Fast setup — recovering VOCs in as little as one hour
Hg vacuum
Oxidizer capacity
VOC recovery start
MDPE Specifications
Engineering specs for EE&G's MDPE fleet. These are the numbers most often requested by site owners, consultants, and regulators when scoping a project.
| Parameter | EE&G MDPE Fleet |
|---|---|
| Vacuum | Up to 28" Hg |
| Oxidizer capacity | 300–600 SCFM |
| Compatible wells | 2"–6" diameter (existing monitoring or recovery wells) |
| Setup to first VOC recovery | As fast as 1 hour |
| Water treatment | 10 GPM, 1,000 lbs carbon, oil/water separator, 4-tray air stripper |
| Site footprint | As little as two parking spots — business stays open |
| Power | Onboard generator — no on-site power required |
| Service area | 41 states |
When MDPE Is the Right Choice
MDPE is one tool in the groundwater remediation toolbox. Here is how it compares to the alternatives EE&G's clients evaluate most often.
vs. Pump-and-treat
Best for: Long-term containment of large dissolved plumes with stable contaminant loading.
MDPE advantage: MDPE recovers free product and vapor in addition to groundwater, so it removes mass orders of magnitude faster on petroleum and chlorinated-solvent sites with NAPL or smear-zone impacts.
vs. Soil vapor extraction (SVE) alone
Best for: Vadose-zone VOC sources sitting well above the water table.
MDPE advantage: When contamination straddles the water table or fluctuates seasonally, MDPE's combined liquid + vapor extraction handles both phases simultaneously instead of leaving the saturated zone untouched.
vs. Air sparging
Best for: Volatilizing dissolved-phase contaminants in the saturated zone.
MDPE advantage: MDPE actively recovers and treats the contaminant mass under high vacuum rather than depending on subsurface volatilization, so it works in tighter formations and avoids uncontrolled vapor migration.
vs. Fixed remediation systems
Best for: Single-source sites where a permanent installation is justified.
MDPE advantage: No capital build-out, no fixed-system maintenance, and no end-of-project decommissioning cost. EE&G's mobile fleet redeploys between sites and across multiple plume areas.
MDPE: Frequently Asked Questions
What is Mobile Dual Phase Extraction (MDPE)?
Mobile Dual Phase Extraction (MDPE) is a trailer-mounted groundwater remediation method that uses high vacuum to pull both contaminated groundwater and vapor from existing wells at the same time. EE&G operates a fleet of MDPE trailers and has deployed the technology across 41 states since 1987.
How does MDPE work?
An MDPE trailer applies up to 28" Hg of vacuum to a monitoring or recovery well. Liquid and vapor are extracted together, separated in a knockout chamber, then the groundwater is treated or hauled off-site and the vapor is destroyed in an electric catalytic oxidizer rated for 300–600 SCFM.
When should I use MDPE instead of pump-and-treat?
MDPE is the better choice when a site has free product, a smear zone, or significant vapor-phase contamination — situations where pump-and-treat removes water for years without meaningfully reducing mass. MDPE recovers liquid and vapor simultaneously, so closure timelines on petroleum and chlorinated-solvent sites are typically much shorter.
How quickly can EE&G mobilize an MDPE trailer?
Because the units are trailer-mounted and self-powered, EE&G can deploy across the 41-state service area on short notice and begin recovering VOCs within roughly one hour of arrival on site.
What contaminants does MDPE remediate?
MDPE is most commonly used for petroleum hydrocarbons (BTEX, MTBE, TPH) and chlorinated solvents (PCE, TCE, vinyl chloride). It is effective on dissolved-phase contamination, free product (LNAPL/DNAPL), and sorbed-phase contamination in the smear zone.
How much area can one MDPE trailer cover?
A single MDPE trailer creates a large radius of influence and can be relocated between wells on the same site to target multiple plume areas. For larger or geographically separated plumes, EE&G stages additional trailers from the fleet.
Does the site need to shut down during MDPE operation?
No. The trailer footprint is as small as two parking spots, the unit runs on its own generator, and operations are designed so retail and commercial sites can stay open during remediation.
Where does EE&G operate its MDPE fleet?
EE&G is headquartered in Azle, Texas with regional offices in Galveston, Texas and Bossier City, Louisiana, and operates the MDPE fleet across 41 U.S. states.
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