Vapor extraction rates for decontaminating soils
- Univ. of Arizona, Tucson, AZ (United States). Dept. of Soil, Water and Environmental Science
Soil vapor extraction (SVE) decontaminates soils containing volatile organic compounds (VOCs) by drawing air through the contaminated zone to a dry well and to the surface. The air evaporates the VOCs and induces in situ biodegradation. An optimal SVE rate minimizes cleanup time, initial and operating costs and the cost of treating the SVE air. Most SVE designs are based on hydrogeology, but air extraction in soils differs greatly from liquid extraction. In addition, liquid VOC flow from a leak differs greatly from water flow in soils. This paper considers gaseous and liquid VOC flow in soils, some factors affecting the optimal SVE flow rate and the effects of the water and heat removal that accompany VOC removal by SVE. Recommendations for fast SVE rates, greater than 100 cfm (160 m{sup 3}/hr) per well,are supported by initial pump tests, by pump manufacturers` guidelines and by assuming vapor equilibrium. Air extraction initially removes VOCs from the major air channels, so fast SVE rates then remove VOCs faster. This air at vapor equilibrium, however, is soon swept out. Thereafter removal is controlled by VOC diffusion from micropores to the mass flow region, the VOC concentrations are below equilibrium and VOC removal is independent of the SVE rate.
- OSTI ID:
- 477257
- Journal Information:
- Pollution Engineering, Journal Name: Pollution Engineering Journal Issue: 3 Vol. 29; ISSN PLENBW; ISSN 0032-3640
- Country of Publication:
- United States
- Language:
- English
Similar Records
TESVE model for design of soil vapor extraction systems with thermal enhancement
TESVE model for design of soil vapor extraction systems with thermal enhancement