A common organic compound used in a large variety of industrial processes. Benzene contamination is common for petroleum, coal tar, and industrial sites.
Benzene is a colorless and highly flammable liquid and is responsible for the aroma around gas stations. It is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of pounds are produced yearly.
Benzene is classified is a carcinogen.
Applicable Remediation Technologies for Benzene
Physical
Air Sparging: Excellent – As the vapor pressure is greater than 1 mm Hg, air sparging is an effective process for groundwater remediation of benzene.
SVE: Excellent – As the vapor pressure is greater than 1 mm Hg, soil vapor extraction is an effective process for soil benzene contamination.
Thermal: Excellent – As benzene is already a volatile organic and will work with SVE at typical soil temperatures (see above), thermally enhanced SVE should be used when the benzene is in low permeability material or short remediation time frames are required.
Pump and Treat: Good to Poor – Generally, pump and treat will be effective at the containment of any aqueous contaminant. Pump and treat is usually not an effective source remedy when significant quantities of non-aqueous mass present (absorbed to soil or non-aqueous phase liquids).
Chemical
In Situ Chemical Oxidation (ISCO): Excellent – A variety of oxidant chemistries can successfully mineralize benzene contamination, with the exception of permanganate.
Biological
Aerobic: Excellent – Benzene degrades readily under aerobic conditions. Often nutrients for microbial degradation can be a limiting factor. The time frame for this technology can be very sensitive to the total mass of contaminant.
Anaerobic: Generally Poor – Benzene can degrade under anaerobic conditions, although the rate of degradation is often much slower than under anaerobic conditions. Field testing should be completed to determine if degradation is occurring at your site.
Absorption
Activated Carbon: Excellent – Readily adsorbs to activated carbon.
Properties
Molecular weight (g/mole): 78.115
Solubility (mg/L): 1,790
Vapor pressure (mm Hg): 94.8
Henry’s Coefficient (unitless): 0.2269011
Organic Carbon Partitioning Coefficient (cm3/g): 145.8