Flameless Thermal Oxidation at the U.S. Department of Energy's Savannah River Site, M Area, Aiken, South Carolina (In Cooperation With the U.S. Department of Energy, Oak Ridge Operations)

Site Name:

Savannah River Site

Location:

Aiken, South Carolina

Period of
Operation:

April to May 1995

Cleanup
Type:

Field demonstration

Vendor:

Bob Wilbourn
Thermatrix, Inc.
(615) 539-9603

Technology:
Post-Treatment (Air) - Flameless Thermal Oxidation

- Flameless Thermal Oxidizer (FTO) is a commercial technology available from Thermatrix, Inc.
- FTO uses a heated packed bed reactor typically filled with saddle- and spherical-shaped inert ceramic pieces to destroy chlorinated and non-chlorinated volatile organic compounds (VOCs) in vapors extracted by a Soil Vapor Extraction (SVE) system.
- Designed to oxidize off-gases without forming PICs or HAPs; not viewed as an incineration technology

Cleanup Authority:
State: Air discharge permits for the Savannah River demonstration site are in place with the South Carolina Department of Health and Environmental Control (SCDHEC)

SIC Code:
9711 (National Security)
3355 (Aluminum Forming)
3471 (Metal Finishing)
Point of Contact:
Jef Walker, DOE, (301) 903-7966
Jim Wright, DOE, (803) 725-5608

Contaminants:
Chlorinated Aliphatics

- Trichloroethene (TCE), tetrachloroethene (PCE), and 1,1,1-trichloroethane (TCA)
- TCE concentrations in the off-gas ranged from 157 to 291 ppm, PCE from 243 to 737 ppm, and TCA from 12 to 21 ppm.

Waste Source:
Surface impoundment (unlined settling basin)

Type/Quantity of Media Treated:
Off-gases (extracted vapors)

- Information not provided on quantity treated

Purpose/Significance of Application:
FTO was demonstrated as an alternative technology for treatment of extracted vapors during an SVE application to oxidize off-gases without forming PICs or HAPs.

Regulatory Requirements/Cleanup Goals:
- The Savannah River site maintains air discharge permits for in situ remediation demonstrations associated with VOCs in non-arid soils and ground water.
- No specific regulatory requirements or cleanup goals were identified for the FTO demonstration.

Results:
This demonstration was evaluated in terms of destruction and removal efficiency (DRE) for specific VOCs and total chlorinated VOCs (CVOCs).

- The FTO unit achieved >99.995% DRE for PCE and >99.95% for TCE and total CVOCs during a 22-day continuous operation testing stage.
- The FTO unit achieved >99.995% DRE for total CVOCs during a 2.5 day testing period where the influent stream was spiked with 950 to 3060 ppm CVOC.

Cost Factors:
- Capital cost for the FTO unit used in the demonstration was $50,000 (for an electrically heated, 5 scfm unit without an integrated caustic scrubber).
- Total operating costs for FTO technology were estimated at $0.72 per pound of CVOC destroyed, including costs for capital recovery, energy, labor, and maintenance.
- No additional details provided on components of capital or operating costs; however, the authors report that FTO costs less per pound of CVOC destroyed than competing technologies such as thermal catalytic technologies.

Description:
From 1958 to 1985, Savannah River Area M conducted manufacturing operations including aluminum forming and metal finishing. Process wastewater from these operations containing solvents (TCE, PCE, and TCA) was discharged to an unlined settling basin at Savannah River, which lead to contamination of ground water and vadose zone soils. Treatment of vadose zone soils has been the subject of several demonstrations (e.g., in situ air stripping), including this investigation of the technical and economic performance of off-gas treatment technologies.

Flameless thermal oxidation (FTO) is a commercial technology used in a demonstration at Savannah River Area M to treat chlorinated VOCs in off-gasses extracted using a SVE system. FTO uses a heated packed bed reactor typically filled with saddle- and spherical-shaped inert ceramic pieces to destroy chlorinated and non-chlorinated VOCs in vapors extracted by a SVE system. The demonstration was based on pumping from one horizontal SVE well at a flow rate of 5 scfm, and the thermal reaction zone in the FTO was maintained at 1400 to 1700 °F. A caustic scrubber was not included in this demonstration because of the relatively small quantity of HCl produced.

This demonstration was evaluated in terms of destruction and removal efficiency (DRE) for specific VOCs and total chlorinated VOCs (CVOCs). The FTO unit achieved >99.99% DRE for PCE, and >99.995% DRE for total CVOCs during a testing period where the influent stream was spiked with CVOC. During the continuous and spike testing phases, no PICs or HAPs were detected in the FTO effluent.