title: Modelling Cr(VI) removal by a combined carbon-activated sludge system.
abstract: The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances in wastewaters; however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaters containing Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludge microorganisms in aerobic batch reactors, (ii) powdered-activated carbon, and (iii) the combined action of powdered-activated carbon and biomass; (b) to propose mathematical models that interpret the experimental results. Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon-biomass system. A Monod-based mathematical model was used to describe the kinetics of Cr(VI) removal in the system S1. A first-order kinetics with respect to Cr(VI) and PAC respectively, was proposed to model the removal of Cr(VI) in the system S2. Cr(VI) removal in the combined carbon-biomass system (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using the activated carbon-biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ), La Plata, Argentina.
authors.forename: A Micaela Ferro
authors.initials: AM
authors.lastname: Orozco
authors.forename: Edgardo M
authors.initials: EM
authors.lastname: Contreras
authors.forename: Noemí E
authors.initials: NE
authors.lastname: Zaritzky
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D002244:Carbon / Q000008:administration & dosage / Q000737:chemistry*; D002857:Chromium / Q000378:metabolism*; D007700:Kinetics; D007785:Lactose; D008956:Models, Chemical; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism; D018508:Water Purification / Q000379:methods
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D002244:Carbon; D007785:Lactose