Experimental Study of an Environmental Remediation of Gulf Coast Crude-Oil-Contaminated Soil Using Low-Temperature Thermal Treatment

Abstract

Laboratory research was conducted to study the remediation of crude-oil-contaminated soil under the "Low-Temperature" burner system. Low temperature burner systems are those which operate below or up to 650 degrees F whereas, those above 650 degrees F are called "High-Temperature" systems. In this study, the effectiveness of remediation processes at three different levels of operating temperatures of 300 degrees F, 650 degrees F, and 2,000 degrees F and three different levels of retention times of 2, 15, and 30 minutes in the burner were investigated. Twenty-nine experimental tests were performed using four different types of oils. The result of the initial soil test showed less than 100 ppm Total Petroleum Hydrocarbon levels. Before Weatherization of four different crude-oil-contaminated soils, the results of Total Petroleum Hydrocarbon (TPH) levels for sample numbers 5318, 5331, 5332, and 5351 were measured 45,000 mg/kg, 26,000 mg/kg, 27,000 mg/kg, and 29,000 mg/kg respectively. After Weathering the samples for two weeks, (average high and low temperatures were recorded at 77.6 degrees F and 67.1 degrees F respectively); the results of TPH levels for sample numbers 5318, 5331, 5332, and 5351 were measured 32,000 mg/kg, 19,000 mg/kg, 15,000 mg/kg, and 28,000 mg/kg respectively. Then After Ashing by combustion, the experimental results of TPH levels for sample numbers 5318, 5331, 5332, and 5351 at 650 degrees F and 30-minutes retention time were measured 980 mg/kg, 3,400 mg/kg, 2,700 mg/kg, and 2,900 mg/kg respectively. Tests conducted in this study include sonication to agitate sample for disrupting cells, bacteria, or tissues; infrared detection to measure TPH levels; and combustion to burn all hydrocarbons. Based on the results of this tests, the study suggested that the cleanup or remediation of hydrocarbon/or non-hydrocarbon compounds by "Low-Temperature" burner system are possible but only at high retention time. The retention time required to achieve this remediation process range from 49, 52, 53, and 52 minutes respectively (figures 1.1-1.4). For the "High-Temperature" burner system, the result of this study showed that at two-minutes retention time, the total remediation of oil-contaminated soil required the burner temperatures of 3,100 degrees F, 2,900 degrees F, 2,600 degrees F, and 3,100 degrees F for sample numbers 5318, 5331, 5332, and 5351 respectively (figures 1.5-1.8). The remediation of petroleum-contaminated soil under low temperature system is technically feasible but may not be economically practical because of the long retention time required to achieve the goal. P. 723^