Dyes biosorption of textile wastewaters in a lab-scale fluidised bed

The production of wastewaters polluted by organic dyes represents one of the most critical drawbacks of textile industries. The adopted decolourization processes are often expensive or ineffective. Characterization of dye adsorption on microbial biomass – biosorption – showed the effectiveness of such alternative remediation process. Previous studies pointed out that inactive biomass of Cunninghamella elegans MUT 2861 was highly effective in removing dyes having different chemical structures for several kind of wastewaters. The present study concerns biosorption of dyes contained in real exhaust wastewater from a dyeing bath of an Italian textile factory. The decolourisation process was characterized in terms of biosorption equilibrium between wastewater and biomass and kinetics of dye biosorption by means of jar tests. A bench-scale fluidised bed was adopted for continuous biosorption tests. Batches of 300-600 m granules of lyophilised C. elegans MUT 2861 biomass were tested in bed fluidised with the real exhaust wastewater. The continuous treatment of wastewater in the biosorbent fluidised bed was described adopting a mathematical model that embodies both thermodynamic and kinetic expressions assessed through devoted experiments.