Vapor Extraction System Research Articles

Applying Groundwater Flow Models in Vapor Extraction System Design

Vapor extraction systems have recently been used in a variety of environmental engineering applications, including controlling methane migration and remediating problems associated with spills of volatile and semi-volatile organic compounds. The differential equations that govern pressure flow of gas and vapor in soil are nonlinear in that gas density depends upon gas pressure. However, if the maximum pressure difference between any two points in the flow field is less than approximately 0.5 atmospheres, the differential equations developed to model groundwater flow provide good approximations to gas transport. Vapor extraction systems generally operate under pressure differences on the order of 0.2 atmospheres. Analytical and numerical groundwater flow models can therefore be used to model vapor and gas transport if the proper set of input variables is defined. Analytical groundwater flow models are used to evaluate the results of a field gas extraction test. The results of these evaluations indicate groundwater models can provide an efficient and readily-accessible tool to aid in designing vapor extraction systems.