In Situ Remediation of TNT Red Water Contaminated Soil: Field Demonstration

Abstract

ABSTRACT In China, about 1.5 × 105 m3 soil was contaminated by TNT red water, which contained mainly dinitrotoluene sulfonates (DNTS). These nitroaromatic explosives are toxic and exhibit human mutagenic and carcinogenic potential. Biotechnology capable of decontaminating these contaminated sites and applicable to a larger scale field application was in urgent need. A two-year pilot study was conducted in the TNT red water contaminated sites (1000 m3). The sites were treated by integrated treatment technologies of “Desorption-Biostimulation and Bioaugmentation-Phytoremediation.” Soil samples were taken every six months to determine the concentration of nitro-aromatic compounds. Acute toxicity and Fluorescein diacetate (FDA) hydrolytic activity tests were conducted to evaluate the remediation effect. After 2 years of remediation, the total nitroaromatic compounds were effectively removed, with the average removal efficiency of 99.88% and 90.47% in sites planted with alfalfa and reed, respectively. The toxicity was significantly reduced. The average luminescence inhibition ratio reduced from 92.64% to 3.37% and 29.16%, respectively. The soil microbial activity was significantly improved, with the highest FDA hydrolase activity in the surface layer. The remediation costs for the treatment of 1 cubic meter of contaminated soil were estimated to approximately $126 US. The integrated technologies used have huge potential for decontaminating munitions contaminated sites.