title: Effect of hydraulic retention time on the biodegradation of complex phenolic mixture from simulated coal wastewater in hybrid UASB reactors.
abstract: This study describes the feasibility of anaerobic treatment of complex phenolics mixture from a simulated synthetic coal wastewater using four identical 13.5L (effective volume) bench scale hybrid up-flow anaerobic sludge blanket (HUASB) (combining UASB+anaerobic filter) reactors at four different hydraulic retention times (HRT) under mesophilic (27+/-5 degrees C) conditions. Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg/L and phenolics concentration of 752 mg/L was used as substrate. The phenolics contained phenol (490 mg/L); m-, o-, p-cresols (123.0, 58.6, 42 mg/L); 2,4-, 2,5-, 3,4- and 3,5-dimethyl phenols (6.3, 6.3, 4.4 and 21.3 mg/L) as major phenolic compounds. The study demonstrated that at optimum HRT, 24h, and phenolic loading rate of 0.75 g COD/(m(3)-d), the phenolics and COD removal efficiency of the reactors were 96% and 86%, respectively. Bio-kinetic models were applied to data obtained from experimental studies in hybrid UASB reactor. Grau second-order multi-component substrate removal model was best fitted to the hybrid UASB reactor. The second-order substrate removal rate constant (k(2(s))) was found as 1.72 h(-1) for the hybrid reactor treating complex phenolic mixture. Morphological examination of the sludge revealed rod-type Methanothrix-like, cells to be dominant on the surface.
authors.affiliation: Centre for Environmental Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India.
authors.forename: Anushuya
authors.initials: A
authors.lastname: Ramakrishnan
authors.forename: Sudhir Kumar
authors.initials: SK
authors.lastname: Gupta
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D003031:Coal; D010636:Phenols / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D003031:Coal; D010636:Phenols; D014874:Water Pollutants, Chemical