Phytotreatment of TNT-Contaminated Groundwater

Abstract

Phytoremediation is a viable technique for treating nitroaromatic compounds, particularly munitions. Continuous flow phyto-reactor studies were conducted at the following three influent concentrations of 2,4,6-trinitrotoluene (TNT): 1, 5, and 10 ppm. A control was also prepared with an influent TNT concentration of 5 ppm. Flow rates were systematically reduced to increase hydraulic retention times (HRT) which ranged from 12 to 76 days. Initially, the control reactor removed TNT as efficiently as the plant reactors. With time, however, the efficiency of the control became less than that of the plant reactors, suggesting that adsorption was initially the mechanism for removal. Up to 100% of the TNT was removed. Aminodinitrotoluene (ADNT) effluent concentration was higher for higher TNT influent concentrations. Increasing the retention time reduced ADNT concentration in the effluent. Supplementary batch studies confirmed that ADNT and diaminonitrotoluene (DANT) were phytodegraded. Preliminary batch studies w...