title: Degradation of p-nitrophenol in a batch biofilter under sequential anaerobic/aerobic environments.
abstract: A combined process anaerobic/aerobic in a single reactor was studied, P-nitrophenol (PNP) was used as the model compound. During the anaerobic stage the target compound is modified in such a way that the intermediate product is more readily biodegradable by the aerobic phase. A pilot biofilter was used for the experiment. The biofilter was packed with a volcanic stone (puzolane) to serve as support to the microorganisms and it was inoculated with activated sludge. The microorganisms were acclimated with an initial concentration of 25 mg PNP/l during 75 days (25 cycles). After 230 days of operation, the reaction time of the cycles was reduced to 11.5 h (8 h for the anaerobic phase and 3.5 h for the aerobic one). The PNP was transformed to p-aminophenol (PAP) in the anaerobic phase, with efficiencies near to 100%. A mineralization of 100% of the PAP was found in the oxidative stage. Global efficiencies of PNP mineralization of 98% were obtained. The reaction rates were 16 mg PNP/l-h (PNP uptake), 14 mg PAP/l-h (PAP formation) and 20 mg/l-h (PAP mineralization).
authors.affiliation: Institute of Engineering, National University of Mexico (UNAM), Environmental Bioprocess Department, Ap. Postal 70-472, 04510 Mexico D.F.
authors.forename: R M
authors.initials: RM
authors.lastname: Melgoza
authors.forename: G
authors.initials: G
authors.lastname: Buitrón
mesh_terms: D001420:Bacteria, Aerobic / Q000502:physiology*; D001421:Bacteria, Anaerobic / Q000502:physiology*; D001673:Biodegradation, Environmental; D019149:Bioreactors; D005374:Filtration; D009596:Nitrophenols / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods; D018508:Water Purification / Q000379:methods; D015262:Xenobiotics / Q000378:metabolism*
chemical_list: D009596:Nitrophenols; D015262:Xenobiotics; C024836:4-nitrophenol