Date of Award

5-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Engineering and Earth Sciences

Committee Member

Kevin Finneran, Committee Chair

Committee Member

Sudeep Popat

Committee Member

Nicole Martinez

Abstract

The fate and degradation rates for the insensitive munition (IM) compound 2,4-Dinitroanisole (DNAN), and its metabolites 2-Methoxy-5-nitroaniline (MENA), 4-Methoxy-3-nitroaniline (iMENA), and 2,4-Diaminoanisole (DAAN), were investigated in municipal wastewater sludge. Data indicates that biodegradation of DNAN is a series of two electron reductions, through MENA or iMENA, to DAAN. However, data also indicate that DAAN adsorbs readily to all sludge. Two different types of sludge were used: anaerobic digester sludge and return activated sludge (RAS). Both were collected from a water resource recovery facility in Greenville, SC.

Experiments were conducted under oxic and anoxic (nitrate-reducing) conditions. Anoxic conditions were maintained with a nitrogen headspace. Experiments began with 100 µM DNAN in unamended, iron-amended, nitrate-amended, and combination bottles. The results revealed that DNAN was biodegraded within all the environments, with rates higher at anoxic conditions. When nitrate was present, degradation was inhibited at MENA. The next experiments began with either 100 µM MENA or DAAN added to the wastewater. Experiments in oxic conditions with MENA showed no degradation and limited removal through adsorption, while experiments with DAAN demonstrated only removal through adsorption. Experiments in anoxic conditions beginning with MENA resulted in biodegradation to DAAN with slower rates than when beginning with DNAN. Nitrate was found to inhibit MENA biodegradation in anoxic conditions as well. Experiments in anoxic conditions beginning with DAAN demonstrated no further biodegradation of DAAN; removal was a result on adsorption with slower rates than seen in the experiments in oxic conditions.

DAAN appears to be a terminal end product of biodegradation. Both environments result in reduction of DNAN to DAAN, but once biodegradation produces DAAN, adsorption occurs at varying rates. Several experiments were conducted which show limited desorption occurs in all environments with desorption favored under oxic conditions with a higher organic content.

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