Influence of Extracellular Polymeric Substances on Anaerobic Biofilms Supported by Polyurethane Foam Matrices

摘要

This work focused on the process of biofilm formation onto polyurethane foam matrices in differential horizontal anaerobic immobilized sludge reactors fed with a glucose-based substrate. The experiments consisted of monitoring the biomass colonization process of foam matrices, regarding to the amount of retained biomass, extracellular polymers (EPS) produced and morphological characteristics of the cells attached to the support. The excretion of polymers seemed to be determinant for the fast colonization process observed, probably being related to the cell fixation on the support. Three colonization phases could be observed based on the excretion of EPS. The two first phases lasted for 16 days and corresponded to the biofilm formation, while the third phase indicated the establishment of the biofilm. Rods are the main organisms attached directly to the foam and responsible for EPS production. The large EPS production onto packed-bed reactors may cause hydrodynamic troubles, thus increasing the head loss, decreasing the hydraulic detention time, and affecting the overall reactor's performance.