Date of Award

Spring 1997

Document Type

Thesis

Degree Name

Master of Science in Civil Engineering - (M.S.)

Department

Civil and Environmental Engineering

First Advisor

Jay N. Meegoda

Second Advisor

Manish Chandra Bhattacharjee

Third Advisor

Dorairaja Raghu

Abstract

In this research, statistical analysis of data from ultrasound enhanced soil washing process was performed. The process was optimized using a statistical model. The model had four factors namely power, solvent:soil, surfactant, and dwell time as process variables. The percentage of removal efficiency was considered as the dependent variable. The results from two full and one partial factorial designs were analysed. Interactions up to third order were considered in the analysis, but the results from full factorial design showed that those of order higher than second had insignificant contributions to the removal of contaminants. Since the higher order interactions of process variables could be neglected, a quadratic model was used to optimize the process conditions. The analysis showed that the ultrasonic power density was the main contributing factor. The analysis results showed that for soil #1, optimum average removal of 83 % was obtained at 32% power, 42 solvent:soil, 0.69% surfactant con., and for a dwell time of 25.5 min. For soil #2, similar results were obtained with lower removal efficiency. The removal efficiency of individual PAHs produce similar conclusions for both soils. A partial factorial design was considered for soil 93 to drastically reduce the number of experiments. The statistical analysis showed that data for partial factorial design can be used to obtain meaningful results and had an optimal removal of 37.67% at 34.24% power, 32.62 solvent:soil, 0.89% surfactant con., and for dwell time of 11.33 min.

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