Banca de DEFESA: MATHEUS PARAISO DE SOUZA
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : MATHEUS PARAISO DE SOUZA
DATE: 30/07/2021
TIME: 14:00
LOCAL: Auditório Pós-Graduação Engenharia Civil - CTG - UFPE
TITLE:
COMBINATION OF REDUCTIVE AND OXIDATIVE MICROBIOLOGICAL PROCESSES FOR DEGRADATION OF THE INSENSITIVE AMMUNITION COMPOUND 2,4-DINITRIANISOL (DNAN)
KEY WORDS:
Nitroaromátics; Aromatic amines; Biorremediation; Biotransformation; Ermegent Explosives; Oxi-reduction.
PAGES: 58
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:
Over time, so-called insensitive munition compounds (IMC) have been used as an alternative to conventional explosives, due to their greater safety during use, transport and storage. But, the use of new compounds creates new environmental problems. The nitroaromatic 2,4-dinitroanisole (DNAN) is an IMC, and is present in several explosive formulations. DNAN is toxic, and can come into contact with the environment through the dissolution and infiltration of unexploded pieces in the soil and in explosives production industries, either by wastewater or by possible leaks. It is known that biological processes are able to reduce the two nitro groups present in DNAN, resulting in the aromatic amine 2,4-diaminoanisole (DAAN). However, DAAN still poses an environmental risk. Aromatic amines such as DAAN are subject to aerobic degradation. Thus, the objective of this dissertation is to present a combination of reducing and oxidative processes for the remediation of DNAN and its biological reduction products. For the study of DNAN reduction, the following electron donors were used: acetate, ethanol, pyruvate, hydrogen and the combination of hydrogen and pyruvate. In addition to these conditions, biotic controls were also carried out without the addition of external donors (endogenous) and abiotic controls with heat-killed biological sludge. The tests also took into account the influence of temperature on the kinetics of DNAN consumption, having been carried out at 20 and 30°C. In abiotic controls, no DNAN consumption was observed during the experiment period. There was no notable influence of the addition of ethanol and acetate on the biological consumption of DNAN, considering that these conditions presented a consumption rate similar to the endogenous control. The condition that presented the fastest DNAN reduction (rate at 30°C) was with the combination hydrogen and pyruvate (311,3 ± 10,0 mM∙d-1∙gVSS-1), followed by the condition with hydrogen only (207,2 ± 6,0 mM∙d-1∙gVSS-1), and from the condition with pyruvate only (36,3 ± 3,0 mM∙d-1∙gVSS-1). These three conditions had an improvement in the consumption kinetics with the increase of the temperature from 20 to 30°C. To study the oxidative consumption of DAAN, nitrate, sulfate and oxygen were tested as electron acceptors under different conditions. Anaerobic conditions were also tested without adding electron acceptors, one with pyruvate as co-substrate and the other without. All conditions were tested with and without biological sludge plus one condition with heat-killed sludge. In the abiotic controls there was no significant change in the concentration of DAAN except in the aerobic condition, in which a relevant autoxidation reaction was observed. DAAN was also consumed in the heat-killed sludge condition, consumed up to a saturation limit of 67,4 mM DAAN∙(gVSS heat-killed sludge) -1. Among the biotic conditions tested, the one with oxygen showed the best consumption kinetics. The conditions of sulfate and without electron acceptors (with and without pyruvate) exhibited similar performances in removing DAAN. The presence of nitrate, however, appeared to inhibit the process. An enrichment culture was developed from the aerobic condition. In it, a profound change in the microbial community was observed, in which about 85% of the relative abundance was of microorganisms that were not classified in the literature, suggesting that the process is carried out by microorganisms that have not yet been described. That said, a combination of an anaerobic step followed by an aerobic one shows promise in the remediation of DNAN and later, DAAN.
BANKING MEMBERS:
Externa à Instituição - CAMILA LEITE MADEIRA - UFMG
Externo à Instituição - GIOVANA TOMMASO - USP
Interna - 1528727 - SAVIA GAVAZZA DOS SANTOS PESSOA