Numerical Modeling Of Groundwater Remediation By Air Sprging

Soil and groundwater are often contaminated by leaked oil and organicsolvents. Air Sparging (AS) and Soil Vapor Extraction (SVE), the most widelyused groundwater and soil remediation technologies, are often used toremediate sites contaminated with oil and organic solvents. Compartmentalizedand lumped-parameter model and Multiphase flow model are both importanttheoretical models for AS and SVE. Numerical modeling of AS and SVE canbe used as tools in engineering design, hence the focus of this research. Themain focus of this research is the use of Multiphase flow model to simulate ASand SVE, as it has the ability to simulate the spatial distribution ofcontaminants.In this thesis, the organism of multiphase flow and solution transportation waspresented first. Based of literature of modeling of AS and SVE, most importantfactors taken into consideration included the seepage of air and water, transportationof contaminants with air and water flow, and the transportation of contaminants fromwater to air. Then the control equations of two phase flow were set up. With thoseequations, unsaturated flow (water flow only) and SVE (air flow only) weresimulated. The simulated results were quite close to the results of physical modelstests. AS was modeled with the two phase flow model next, and the resultshowed that the simulated Zone of Influence (ZOI) was quite similar to thatobtained using centrifugal tests. Parameter analysis showed that spargingpressure and soil type have notable influence on ZOI; air compressibility wasanother important factor, which can not be ignored in AS modeling.The process of contaminants removal during AS was also simulated. Thesimulation showed that contaminants within ZOI could be effectivelyremoved while those outside ZOI could not be remediated. Simulation alsoshowed that increasing the sparging pressure could make the removal ofcontaminants faster. The model was also used to simulate AS with SVE at thesame time, and the result showed that SVE would not contribute to the removal of contaminant in water.This research proved that the numerical model used in this research is applicablefor simulating AS and SVE. The model can be used to simulate the ZOI and theremoval of contaminants. Free-phase NAPLs were not considered in this research andit should be taken into consideration in future studies.