SVE OFF-GAS TREATMENT
The vapor removed from contaminated soil using the Soil Vapor Extraction (SVE) technique must be treated to remove the hazardous components. Two methods are generally available – treatment using activated carbon or combustion treatment. Selecting either option is dependent on various factors:
VGAC – Vapor Phase Granular Activated Carbon
The contaminated vapor is passed through a series of carbon beds sized for flow rates and expected contaminant loading. VGAC advantages / disadvantages include:
- Time-tested and readily available
- Suited for non-heavily contaminated streams
- Low operating expense
- Waste Disposal Costs accrue
- Requires frequent On-Site effluent concentration measurements
Combustion Treatment / Cat-Ox
Treating the vapor stream using combustion / oxidation is available two ways:
Thermal Oxidation which is run at temperatures ranging from 1350°F to 1500°F (730°C-815°C).
- Catalytic Oxidation which uses a catalyst to facilitate a lower operating temperature ranging from 600°F to 800°F (315°C-430°C).
- At NES we have integrated various Cat-Ox systems with our SVE systems. Advantages / Disadvantages include:
- Treats elevated concentration levels
- Eliminates hazardous waste removal activities
- Rental options are widely available for use with newly installed systems generating elevated contaminant levels
- High fuel & utility costs can be expected
- Electrical Controls & Power distribution costs increase
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