CIDCA   05380
CENTRO DE INVESTIGACION Y DESARROLLO EN CRIOTECNOLOGIA DE ALIMENTOS
Unidad Ejecutora - UE
artículos
Título:
Hexavalent chromium removal using aerobic activated sludge batch systems added with powdered activated carbon
Autor/es:
A.M. FERRO OROZCO; EDGARDO CONTRERAS; N. BERTOLA; N.E. ZARITZKY
Revista:
WATER S.A.
Referencias:
Año: 2006
ISSN:
0378-4738
Resumen:
The addition of powdered activated carbon (PAC)
has been proposed as a suitable technique to protect the activated sludge
against toxic wastewaters. However, the literature data describing the combined
effect of PAC addition on the Cr(VI) removal using activated sludge are scarce.
The objectives of this study were to investigate the effect of the initial
Cr(VI) concentration, PAC and an electron donor addition on the Cr(VI) removal
using aerobic activated sludge batch reactors.
The following
Cr(VI) removal systems were tested:
activated sludge alone; activated sludge with an external electron donor
(5 g/ℓ of lactose);
activated sludge with PAC addition (4 g/ℓ); activated sludge
with both PAC and lactose; and PAC alone. The obtained results showed that activated sludges are capable of removing
Cr(VI) via its reduction to Cr(III) only if a suitable electron donor (such as
lactose) is available. For initial Cr(VI) concentration lower than 10 mg/ℓ, biomass alone can remove 100 % of the
Cr(VI). However, for higher initial Cr(VI) concentrations, removal efficiencies
(RE) of system with PAC were higher than RE corresponding
to system without PAC. In addition, as the initial Cr(VI) concentration
increased, the rate of Cr(VI) removal and RE values decreased
reflecting loss of metabolic activity of the activated sludge due to the
toxicity of Cr(VI); however, this inhibition was less in systems with PAC. Whereas the
removal of Cr(VI) using powdered activated carbon (PAC) alone is negligible,
the addition of PAC can improve the biological reduction of Cr(VI) due to the
stimulating or protective effect against the Cr(VI) toxicity. This protective
effect was also observed in respiratory activity of the biomass