Continuous detoxification, transformation, and degradation of nitrophenols in upflow anaerobic sludge blanket (UASB) reactors
- Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology
The anaerobic transformation and degradation of nitrophenols by granular sludge was investigated in upflow anaerobic sludge blanket (UASB) reactors continuously fed with a volatile fatty acid (VFA) mixture as the primary substrate. During the start-up, subtoxic concentrations of 2-nitrophenol (2-NP), 4-nitrophenol (4-NP), and 2, 4-dinitrophenol (2, 4-DNP) were utilized. 4-NP and 2, 4-DNP were readily converted to the corresponding aromatic amine; whereas 2-NP was converted to nonaromatic products via intermediate formation of 2-aminophenol (2-AP). These conversions led to a dramatic detoxification of the mononitrophenols because the reactors treated the nitrophenolics at the concentrations which were over 25 times higher than those that caused severe inhibition. VFA removal efficiencies greater than 99% were achieved in both reactors at loading rates greater than 11.4 g COD per liter of reactor volume per day even at volumetric loading of mononitrophenols up to 910 mg/L {center_dot} d. The sludges obtained from each of the reactors at the end of the continuous experiments were assayed for their specific nitrophenol reducing activity in the presence of different primary substrates. Reduction rates of 45 and 26 mg/g volatile suspended solids per day were observed for 2-NP and 4-NP, respectively, when utilizing the VFA mixture as primary substrate.
- OSTI ID:
- 287546
- Journal Information:
- Biotechnology and Bioengineering, Vol. 51, Issue 4; Other Information: PBD: 20 Aug 1996
- Country of Publication:
- United States
- Language:
- English
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