TY - JOUR
T1 - Continuous treatment of the insensitive munitions compound N-methyl-p-nitro aniline (MNA) in an upflow anaerobic sludge blanket (UASB) bioreactor
AU - Olivares, Christopher I.
AU - Wang, Junqin
AU - Silva Luna, Carlos D.
AU - Field, Jim A.
AU - Abrell, Leif
AU - Sierra-Alvarez, Reyes
N1 - Funding Information:
This study was supported by the Strategic Environmental Research and Development Program (SERDP award # ER-2221 ). Some analyses were performed by the Arizona Laboratory for Emerging Contaminants (ALEC) with support from the National Science Foundation (NSF CBET award # 0722579 ) and the company AB Sciex . Sofia Tenorio is thanked for her assistance with some experiments. CIO and CDSL were funded in part by scholarships from the Mexican National Council for Science and Technology (CONACyT) . CIO was also supported by the training core of University of Arizona Superfund Research Program ( National Institute of Environment and Health Sciences award # NIH ES-04940 ).
PY - 2016/2/1
Y1 - 2016/2/1
N2 - N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized; however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d-1. Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA.
AB - N-methyl-p-nitroaniline (MNA) is an ingredient of insensitive munitions (IM) compounds that serves as a plasticizer and helps reduce unwanted detonations. As its use becomes widespread, MNA waste streams will be generated, necessitating viable treatment options. We studied MNA biodegradation and its inhibition potential to a representative anaerobic microbial population in wastewater treatment, methanogens. Anaerobic biodegradation and toxicity assays were performed and an up-flow anaerobic sludge blanket reactor (UASB) was operated to test continuous degradation of MNA. MNA was transformed almost stoichiometrically to N-methyl-p-phenylenediamine (MPD). MPD was not mineralized; however, it was readily autoxidized and polymerized extensively upon aeration at pH = 9. In the UASB reactor, MNA was fully degraded up to a loading rate of 297.5 μM MNA d-1. Regarding toxicity, MNA was very inhibitory to acetoclastic methanogens (IC50 = 103 μM) whereas MPD was much less toxic, causing only 13.9% inhibition at the highest concentration tested (1025 μM). The results taken as a whole indicate that anaerobic sludge can transform MNA to MPD continuously, and that the transformation decreases the cytotoxicity of the parent pollutant. MPD can be removed through extensive polymerization. These insights could help define efficient treatment options for waste streams polluted with MNA.
KW - Anaerobic
KW - Biodegradation
KW - Insensitive munitions
KW - Microbial toxicity
KW - N-methyl-p-nitroaniline
KW - Nitroaromatic
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U2 - 10.1016/j.chemosphere.2015.09.092
DO - 10.1016/j.chemosphere.2015.09.092
M3 - Article
C2 - 26454121
AN - SCOPUS:84953807359
VL - 144
SP - 1116
EP - 1122
JO - Chemosphere
JF - Chemosphere
SN - 0045-6535
ER -