title: Removal of high phenol concentrations with adapted activated sludge in suspended form and entrapped in calcium alginate /cross-linked poly(N-vinyl pyrrolidone) hydrogels.
abstract: The present work evaluates the aerobic removal of 0.25-2 g/L of phenol by adapted activated sludge in batch and continuous reactors, in suspended form and trapped in polymeric hydrogel beads of calcium alginate(1%) and cross-linked poly(N-vinyl pyrrolidone), x-PVP (4%). The mechanical and chemical resistance of the entrapping hydrogel was also evaluated in three different media: (I) rich in phosphate and ammonium ions; (II) using alternate P and N sources, and (III) without nutrients. The adapted consortium removed phenol concentrations up to 2 g/L more efficiently in the immobilized systems. A decrease in phenol removal rate was observed as the food/microorganisms (F/M) ratio increased. A zero-order kinetics was observed with phenol concentrations > 1 g/L and a first-order kinetics at concentrations < 1 g/L. The best response (100% removal) was in the continuous reactors using type II medium, with a hydraulic residence time (HRT) of 12.5 h, an influent pH = 5, and an F/M ratio below 0.25. The immobilizing matrix deteriorated after 170 h of use in continuous reactors, especially with media I and II, probably due to the attrition forces, to chemical weakness of the material, and to the pressure of the bacterial growth inside the bead.
authors.affiliation: Departamento de Ingenierías y de Ingeniería, Universidad Iberoamericana A.C., Prol. Paseo de la Reforma 880, Lomas de Santa Fe, México, DF 01210. margarita.hernandez@uia.mx
authors.forename: Margarita
authors.initials: M
authors.lastname: Hernández-Esparza
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Doria-Serrano
authors.forename: Gabriela
authors.initials: G
authors.lastname: Acero-Salinas
authors.forename: F Alberto
authors.initials: FA
authors.lastname: Ruiz-Treviño
mesh_terms: D000464:Alginates / Q000737:chemistry*; D001420:Bacteria, Aerobic / Q000378:metabolism*; D001673:Biodegradation, Environmental; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry; D019800:Phenol / Q000302:isolation & purification / Q000493:pharmacokinetics*; D011205:Povidone / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods; D012722:Sewage / Q000382:microbiology*
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020100:Hydrogels; D012722:Sewage; D019800:Phenol; D020723:Glucuronic Acid; D011205:Povidone