Chlorinated Solvents

What are Chlorinated solvents ? 

Chlorinated solvents are industrial chemicals widely used for degreasing, metal cleaning, dry cleaning and chemical manufacturing. Due to decades of industrial use, they are among the most common groundwater and soil contaminants worldwide.

Chlorinated solvents contamination is typically associated with:

• Metal degreasing facilities
• Aerospace and automotive industries
• Dry cleaning operations
• Chemical manufacturing plants
• Electronics production facilities
• Military installations
• Former industrial brownfields
• Hazardous waste disposal sites

The most common Chlorinated Solvents are the following : 

PCE Perchloroethylene	TCE Trichloroethylene	cis-1,2-DCE Dichloroethylene	VC Vinyl Chloride
1,1,1-TCA Trichloroethane	1,1-DCA Dichloroethane	CT Carbon Tetrachloride	CF Chloroform

Many chlorinated solvents are classified as volatile organic compounds (VOCs) and can migrate through soil, groundwater and soil gas.

Why are chlorinated solvents a concern?

Unlike hydrocarbons, chlorinated solvents are often denser than water and can migrate deep below the groundwater table.

Potential impacts include:

💧 Groundwater contamination

💨  Vapor intrusion into buildings

🧬 Carcinogenic and toxic effects

🏠 Indoor air quality concerns

⚠️ Long-term environmental liabilities

Once released, chlorinated solvents can persist in the subsurface for decades and act as continuous sources of groundwater contamination.

Remediation Strategies - State of the Art

Chlorinated solvent contamination is notoriously difficult to remediate because contaminants often migrate deep into the subsurface and become trapped in low-permeability soils.

Technology	Contaminant Removal	Speed	Long-Term Liability	Main Limitations
Pump & Treat	🟠 Partial	🔴 Slow	🟠 Medium	Often requires decades of operation
Soil Vapor Extraction	🟠 Partial	🟢 Fast	🟠 Medium	Limited in saturated zones
Chemical Oxidation	🟠 Partial	🟠 Medium	🟠 Medium	Uneven distribution in heterogeneous soils
Bioremediation	🟠 Partial	🔴 Slow	🟠 Medium	Long treatment periods
Containment	🔴 No	🟢 Fast	🔴 High	Contamination remains in place
Thermal Desorption / ISTD	🟢 Yes	🟢 Fast	🟢 Low	Requires thermal infrastructure and might need groundwater management

For source-zone remediation, thermal treatment is widely recognized as one of the most effective technologies because it physically removes contaminants from both soil and groundwater.

Chlorinated solvents are particularly challenging contaminants because they often migrate below the groundwater table and become trapped in low-permeability soils.

Haemers Technologies combines thermal desorption, vacuum extraction and, when required, multi-phase extraction (MPE) to efficiently remove chlorinated solvents from both soil and groundwater source zones.

Targeted temperature is set from 70 to 99°C. 

🔥 1. Controlled Heating

Smart Burners™ gradually heat the contaminated soil and groundwater through thermal conduction.

The heat propagates uniformly through both saturated and unsaturated zones, reaching contaminants trapped deep below the water table.

🌡️ 2.  Increased Volatility and Mass Transfer

As temperature rises, the vapor pressure of chlorinated solvents increases dramatically.

Compounds such as PCE, TCE and DCE become significantly more volatile, allowing them to desorb from soil particles and transfer from groundwater into the vapor phase.

This thermal enhancement accelerates contaminant recovery even in clays, silts and other low-permeability formations where conventional technologies often struggle.

💧  3.  Treatment of Saturated Zones and DNAPL Sources

Unlike many remediation technologies, thermal treatment remains highly effective below the groundwater table.

Heating reduces contaminant viscosity, increases diffusion rates and promotes the removal of dense non-aqueous phase liquids (DNAPLs), which are often responsible for long-term groundwater contamination.

This makes thermal remediation particularly effective for:

• PCE source zones
• TCE plumes
• DNAPL accumulations
• Saturated clays and silts
• Deep groundwater contamination

💨  4.  Vacuum and Multi-Phase Extraction

As contaminants become mobile and volatilize, they are continuously recovered through vacuum extraction wells.

For highly saturated sites, Haemers can integrate Multi-Phase Extraction (MPE) systems to simultaneously recover:

✓ Soil vapors

✓ Contaminated groundwater

✓ Free-phase contaminants (DNAPL)

✓ Dissolved contaminants

The combination of thermal treatment and MPE significantly accelerates mass removal rates compared to conventional groundwater remediation approaches.

🧪 5. Advanced Vapor Treatment

Extracted vapors are safely treated using:

✓ Condensation units

✓ Activated carbon 

✓ Acid gas treatment

✓ Continuous emissions monitoring

Key Benefits

🎯 Permanent Source Removal

Chlorinated solvents are removed from soil and groundwater source zones rather than contained.

📈 High Removal Efficiency

Thermal treatment routinely achieves remediation targets for PCE, TCE, DCE, vinyl chloride and related compounds.

⚡ Fast Remediation

Projects are completed within months rather than years or decades of conventional groundwater treatment.

💧 Groundwater Protection

Eliminates the source of contamination and significantly reduces plume expansion.

🛡️ Reduced Long-Term Liability

Removes persistent contaminants and minimizes future environmental risks.