Biotreatment of Red Water—A Hazardous Waste Stream from Explosive Manufacture — with Fungal Systems

Abstract

Improper management of red water generated during the manufacture of trinitrotoluene (TNT) is an environmental concern because it can result in soil and groundwater contamination. Past methods for the management of this hazardous waste stream did not fully meet pollution compliance or were not cost effective. The lignin peroxidase (ligninase) secreted by the white rot fungus (Phanerochaete chrysosporium) has been shown in other studies to degrade a broad spectrum of organic pollutants. In this study, the efficacy of treating red water with the P. chrysosporium system was investigated. Red water samples obtained from a munition plant were pretreated with ultraviolet (UV) light and incubated under various conditions with fungal culture or crude extracellular enzyme prepared from the culture. The treated samples were analyzed for decolorization and ligninase activity and by UV spectral analysis, high performance liguid chromatography (HPLC) metabolite analysis, and bacterial toxicity screening. Red color intensity was reduced in all treated samples. UV spectral analysis showed a progressive decrease in the aromatic region (200-300 nm). HPLC analysis demonstrated a decrease in the 2,4,6-trinitrobenzenesulfonic acid peak and diminished TNT, 2,4-dinitrotoluene (DNT), and 2,6-DNT peaks in red water samples treated with concentrated fungal enzyme preparation. The same treatment also reduced the toxicity of the red water as tested by a bioassay. The results of this study suggest that the white rot fungal system is effective in biodegrading and reducing biotoxicity of red water in one week under controlled laboratory conditions.