| Technology | Contaminant Destruction or Transfer? | Complete Technology or Part of Treatment Train? | End Products | Effectiveness | Ability to work in clay type soils | Installation Notes | Ease of O&M1 | Regulatory acceptance | Notes | |||
| CURRENT TECHNOLOGY | ||||||||||||
| Pump and Treat | Transfer | Part of treatment train or complete technology | Clean water and air as a complete technology. Contaminated water as part of a treatment train. | Takes a long time to reach cleanup goals | Not very efficient | Fairly Easy | Lengthy O&M period | Yes | Losing favor as a preferred alternative | |||
| Air Stripping (used in conjunction with Pump and Treat) | Transfer - Contaminant vented into atmosphere or transferred to carbon filter | Part of treatment train | Clean water and contaminated off gas | Effective treatment | Not Applicable | Fairly Easy | Requires periodic maintenance and filter changes | Yes | Doesn't provide TCE destruction | |||
| Air Sparging | Both - Volatizes TCE and enhances bioremediation | Can be complete technology or part of treatment train | May create contaminated off gas. Soil vapor extraction may be required to further remediate the site. | Effective in porous geology | May create preferential channels or be ineffective | Fairly Easy | Simple O&M | Yes | ||||
| Air Sparging with Soil Vapor Extraction | Mostly Transfer - Volatizes TCE and enhances bioremediation | Can be complete technology | Effective in porous geology | May create preferential channels | Fairly Easy | Requires off-gas treatment | Yes | More effective than air sparging alone | ||||
| Carbon Adsorption (vapor phase) | Transfer | Part of treatment train | Clean air and TCE-contaminated carbon | Effective treatment | Not Applicable | Fairly Easy | Requires periodic change of carbon | Yes | ||||
| Flameless Thermal Oxidizer | Contaminant destruction - 99% achievable | Part of treatment train | Clean air and hydrochloric acid that may require use of a caustic scrubber. | Effective treatment | Not Applicable | Fairly Easy | Requires periodic maintenance and catalyst replacement | Yes | Not as effective on TCE as petroleum hydrocarbons | |||
| Catalytic Oxidation | Contaminant destruction - 99% achievable | Part of treatment train | Clean air | Effective treatment | Not Applicable | Fairly Easy | Requires periodic maintenance and catalyst replacement | |||||
| EMERGING TECHNOLOGY | ||||||||||||
| Natural Attenuation | Contaminant Destruction | Can act alone or be enhanced | Clean ground water | Effective over a long period of time | Effective | Not Applicable | Not Applicable | Very Limited | Sampling and modeling required to demonstrate conditions are appropriate | |||
| In Situ Air Sparging with Horizontal Wells | Both - Volatizes TCE and enhances bioremediation. VOCs transferred via extraction wells | Can be complete technology or part of treatment train | May create contaminated off gas. Soil vapor extraction may be required to further remediate the site. | Effective in porous geology | Not very efficient | Horizontal well placement may be difficult | Requires off-gas treatment | Limited, due to youth of technology | More efficient than vertical air sparging | |||
| Methane Enhanced Bioremediation Using Horizontal Wells | Both - Volatizes TCE and enhances bioremediation. VOCs transferred via extraction wells | Can be complete technology or part of treatment train | Should be clean ground water. May create contaminated off gas. Soil vapor extraction may be required to further remediate the site. | Effective in most geologies | Effective, due to methanogenesis | Horizontal well placement may be difficult | Requires off-gas treatment | Limited, due to youth of technology | More efficient than horizontal air sparging alone. Enhances bioremediation | |||
| Reactive Walls or Cells (Iron Filings) | Contaminant destruction via reductive dehalogenation | Complete technology | Clean ground water | Effective in shallow aquifer underlain by confining layer | Effective with sufficient groundwater flow | Requires in-depth knowledge of site hydrology and heavy equipment to install | No moving parts to maintain or filters to change | Limited. In field test phase | Provides for complete destruction of TCE and harmful daughter products | |||
| UV Oxidation | Contaminant destruction | Part of treatment train | Clean ground water, carbon dioxide, and salts | Effective | Not Applicable | May require pre-treatment of water if turbid | Requires handling and storage of powerful oxidizers | Limited. In field test phase | ||||
| Six-Phase Soil Heating | Both - Sterilizes soil and drives off volatile TCE which is removed via SVE | Can be complete technology | Contaminated off gas | Effective in clay soils | Effective | Requires large power source and site restrictions | Requires off-gas treatment and maintenance of electrodes | Limited. In field test phase | ||||
| Dynamic Underground Stripping of Volatile Organic Compounds | Both - Sterilizes soil and drives of volatile TCE which is removed by SVE | Part of treatment train | Contaminated off gas and ground water | Provides rapid remediation | Effective | Fairly Easy | Requires off-gas treatment | Limited. In field test phase | 25 to 40 times more effective than pump and treat alone | |||
| Lasagna Process | Can be both | Can be complete technology or part of treatment train | If used in-situ, the end products are clean ground water and soils. As part of a treatment train, contaminated off gas and water may be extracted. | Effective in clay soils | Very Effective | Moderate Difficulty | Short O&M period | Limited. In field test phase | Field tested at Rickenbacker ANGB, Ohio | |||
| Phytoremediation | Can be both | Can be complete technology or part of treatment train | Clean groundwater is an end product. Contaminated plant tissues may also occur. | Effective in clay soils | Effective | Fairly Easy | O&M may be limited to LTM | Limited. In field test phase | Field tested at Naval Air Station Fort Worth, Texas | |||
| Vacuum Vapor Extraction | Both - remediates ground water and vadose zone while volatile TCE is treated ex situ | Part of treatment train | TCE-contaminated off gas. Ground water remains in-situ. | Effective in clay soils | Effective | Fairly Easy | Requires off-gas treatment | Limited | ||||
| Oxygen Enhancement with Hydrogen Peroxide | Contaminany Destruction/Bioremediation | Can be complete technology | Clean ground water | Effective | Moderately effective | Fairly Easy | Requires delivery of hydrogen peroxide | Limited | ||||
| RESEARCH NOT YET FIELD TESTED | ||||||||||||
| Silent Discharge of Plasma Decomposition | Contaminant destruction | Complete technology | Carbon dioxide and chlorine | Still in laboratory | ||||||||
| Fixed-Bed Photocatalysts for Solar Decontamination of Water | Contaminant destruction | Part of treatment train | Clean ground water | Still in laboratory | ||||||||
| 1. All remedial actions require some amount of long-term monitoring (LTM) that may be considered O&M. | ||||||||||||
| Items in this column reflect requirements above and beyond standard LTM. |
Last Updated on 1/10/98
By DH