Removal of Cr(VI) from aqueous solutions by a bacterial biofilm supported on zeolite: optimisation of the operational conditions and scale-up of the bioreactor

• Main Author: Pazos, M.
• Publication Date: 2010
• Other Authors: Branco, Mónica, Neves, Isabel C., Sanromán, M. A., Tavares, M. T.
• Format: Article
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: https://hdl.handle.net/1822/11338
• topic: Arthrobacter viscosus; 13X zeolite; Bioreactor; Cr removal; Scale-up; Science & Technology

The aim of this study was to investigate the feasibility of a bioreactor system and its scale-up to remove Cr(VI) from solution. The bioreactor is based on an innovative process that combines bioreduction of Cr(VI) to Cr(III) by the bacterium Arthrobacter viscosus and Cr(III) sorption by a specific zeolite. Batch studies were conducted in a laboratory-scale bioreactor, taking into account different operating conditions. Several variables, such as biomass concentration, pH and zeolite pre-treatment, were evaluated to increase removal efficiency. The obtained results suggest that the Cr removal efficiency is improved when the initial biomass concentration is approximately 5 g L–1 and the pH in the system is maintained at an acidic level. Under the optimised conditions, approximately 100 % of the Cr(VI) was removed. The scale-up of the developed biofilm process operating under the optimised conditions was satisfactorily tested in a 150-L bioreactor.