Modelling Cr(VI) removal by a combined carbon-activated sludge system

FERRO OROZCO A.M.; CONTRERAS E.; ZARITZKY N.

JOURNAL OF HAZARDOUS MATERIALS.

Elsevier

Año: 2008 vol. 150 p. 46 - 52

0304-3894

The combined carbon-activated sludge process has been proposed as an alternative to protect the biomass against toxic substances inwastewaters;however, the information about the effect of powdered-activated carbon (PAC) addition in activated sludge reactors for the treatment of wastewaterscontaining Cr(VI) is limited. The objectives of the present study were: (a) to evaluate the removal of hexavalent chromium by (i) activated sludgemicroorganisms 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.15Different Cr(VI) removal systems were tested: (S1) biomass (activated sludge), (S2) PAC, and (S3) the combined activated carbon–biomasssystem.AMonod-based mathematical modelwas used to describe the kinetics of Cr(VI) removal in the system S1.Afirst-order kinetics with respectto 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–biomasssystem (S3) was faster than both Cr(VI) removal using PAC or activated sludge individually. Results showed that the removal of Cr(VI) using theactivated carbon–biomass system (S3) was adequately described by combining the kinetic equations proposed for the systems S1 and S2.