Applications of Biofilm in the Degradation of Contaminants in Industrial Effluents-A Review

In this paper, it is presented a review about applications of biofilms in the degradation of contaminants in industrial effluents. Biofilms are typically comprised of water, microorganisms, extracellular polymeric substances (EPS), retained particles and dissolved and adsorbed substances. Water is the most significant fraction of the total mass of the biofilm, and it can vary from 70 to 95%. Polymeric substances represent around 70 to 95% of the organic material of the dry biofilm mass. The composition determines important properties of the biofilm, such as the adhesion force, elasticity, and adsorption capacity. Studies have shown that adhered cultures are less affected than suspended cultures by environmental changes: temperature, pH, nutrient concentration, metabolic products and toxic substances. In this paper, it is shown the application of a reactor with adhered biomass to the removal of BTX (benzene, toluene and o-xylene) compounds, in the fixed bed column with biofilm, for the different concentrations and feed flows. The results presented indicate a strong potential for the industrial use of the biodegradation system described herein, comprised of a metabolically active bacterial biofilm, supported on activated carbon, since there was bacterial reproduction in the biofilm and consumption of BTX compounds by this biomass.