Design considerations for soil cleanup by soil vapor extraction

Soil remediation process by heated soil vapor extraction system has drawn considerably attention for the last few years. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. Our present study is concentrated on modeling one transient Heated Soil Vapor Extraction System and predicting the time required for effective remediation. The process developed by Advanced Remedial Technology, consists of a heating source pipe and the extraction well embedded in the soil. The number of heat source pipes and the extraction wells depends on the type of soil, the type of pollutants, moisture content of the soil and the size of the area to be cleaned. The heat source heats the soil, which is transported in the interior part of the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then driven out of the soil by the extraction well. The extraction well consists of the blower which would suck the vaporized gases out of the system. A three-dimensional meshed geometry was developed using gambit. Different boundary conditions were used for heating and suction well and for other boundaries. Concentrations of different chemicals were collected from the actual site and this data was used as an initial condition. The analysis uses the species transport and discrete phase modeling to predict the time required to clean the soil under specific conditions. This analysis could be used for predicting the changes of chemical concentrations in the soil during the remediation process. This will give us more insight to the physical phenomena and serve as a numerical predictive tool for more efficient process.

Download Full-text

Research progress in the enhancement technology of soil vapor extraction of volatile petroleum hydrocarbon pollutants

Environmental Science Processes & Impacts ◽

10.1039/d1em00170a ◽

2021 ◽

Author(s):

Weikai Cao ◽

Lei Zhang ◽

Yue Miao ◽

Lufan Qiu

Keyword(s):

Petroleum Hydrocarbon ◽

Research Progress ◽

Soil Vapor Extraction ◽

Vapor Extraction ◽

Hydrocarbon Pollution ◽

Enhancement Technology

At present, volatile petroleum hydrocarbon pollution in soil is still widespread and serious in China.

Download Full-text

Steady State Analysis of Heated Soil Vapor Extraction Process With Air Sparging

Heat Transfer: Volume 2 ◽

10.1115/ht2005-72272 ◽

2005 ◽

Author(s):

P. M. Mohan Das ◽

R. S. Amano ◽

T. Roy ◽

J. Jatkar

Keyword(s):

Extraction Process ◽

Soil Vapor Extraction ◽

Air Sparging ◽

Saturated Zone ◽

Vapor Extraction ◽

Combined System ◽

Discrete Phase Modeling ◽

Discrete Phase ◽

Time Required ◽

Heated Soil

Heated Soil Vapor Extraction (HSVE), developed by Advanced Remedial Technology is a Soil remediation process that has gained significant attention during the past few years. HSVE along with Air sparging has been found to be an effective way of remediating soil of various pollutants including solvents, fuels and Para-nuclear aromatics. The combined system consists of a heater/boiler that pumps and circulates hot oil through heating wells, a blower that helps to suck the contaminants out through the extraction well, and air sparging wells that extend down to the saturated region in the soil. Both the heating wells and extraction wells are installed vertically in the saturated region in contaminated soil and is welded at the bottom and capped at the top. The heat source heats the soil and the heat is transported inside the soil by means of conduction and convection. This heating of soil results in vaporization of the gases, which are then absorbed by the extraction well. Soil vapor extraction cannot remove contaminants in the saturated zone of the soil that lies below the water table. In that case air sparging may be used. In air sparging system, air is pumped into the saturated zone to help flush the contaminants up into the unsaturated zone where the contaminants are removed by SVE well. In this analysis an attempt has been made to predict the behavior of different chemicals in the unsaturated and saturated regions of the soil. This analysis uses the species transport and discrete phase modeling to predict the behavior of different chemicals when it is heated and absorbed by the extraction well. Such an analysis will be helpful in predicting the parameters like the distance between the heating and extraction wells, the temperature to be maintained at the heating well and the time required for removing the contaminants from the soil.

Download Full-text

Uncertainties in cleanup times for soil vapor extraction

Water Resources Research ◽

10.1029/1999wr900305 ◽

2000 ◽

Vol 36 (3) ◽

pp. 679-692 ◽

Cited By ~ 22

Author(s):

Joel Massmann ◽

Scott Shock ◽

Lise Johannesen

Keyword(s):

Soil Vapor Extraction ◽

Vapor Extraction

Download Full-text