A Practical Approach to the Design, Operation, and Monitoring of In Situ Soil‐Venting Systems

Abstract

When operated properly, in situ soil venting or vapor extraction can be one of the most cost‐effective remediation processes for soils contaminated with gasoline, solvents, or other relatively, volatile compounds. The components of soil‐venting systems are typically off‐the‐shelf items, and the installation of wells and trenches can be done by reputable environmental firms. However, the design, operation, and monitoring of soil‐venting systems are not trivial. In fact, choosing whether or not venting should be applied at a given site is a difficult decision in itself. If one decides to utilize venting, design criteria involving the number of wells, well spacing, well location, well construction, and vapor treatment systems must be addressed. A series of questions must be addressed to decide if venting is appropriate at a given site and to design cost‐effective in situ soil‐venting systems. This series of steps and questions forms a “decision tree” process. The development of this approach is an attempt to identify the limitations of in situ soil venting, and subjects or behavior that are currently difficult to quantify and for which future study is needed.

Field vapor extraction test and long-term monitoring at a PCE contaminated site

“…(5), C L is in ppm. For PCE at 20 • C, p = 13.7 mmHg, C L = 130 ppm [6], and from Eq. (5), K H = 0.95.…”

“…Under the condition of a steady-state radial flow, the relationship between the air permeability and the flow rate is as follows [6]:…”

“…Under the condition of a steady-state radial flow (flow direction is horizontal and no air from the ground surface enters the ground), the relationship between radius and absolute pressure is given as follows [6]:…”

Review Report: Building C-400 Thermal Treatment 90 Percent Remedial Design Report and Site Investigation, Pgdp, Paducah, Kentucky

“…A pseudo-steady solution for confined, one-dimensional, radial air flow is available (Johnson et al, 1990) as an order-of-magnitude check for the design basis: (6) suggests the maximum flow from a shallow extraction well is about 4 scfm for an applied vacuum at the wellhead of 0.5 atmospheres. The design rate cited in Table 1.2 of Appendix B is 8 scfm per well.…”

Optimal flow rates and well locations for soil vapor extraction design

“…The use of soil vapor extraction SVE as a remediation technology for the unsaturated zone is increasing and can be more efficient and cost-effective in comparison to Ž . remedial strategies like excavation or pump-and-treat Johnson et al, 1990 . In SVE, air is introduced into the unsaturated zone to increase the volatilization of the contaminant and a vacuum is created by extracting the air and contaminant vapor using extraction Ž .…”