<p> The adsorption of residual organic molecules generated during the metabolic activity of bacteria was investigated. </p> <p> At first a number of potential adsorbants and ion exchange resins were selected with different average pore diameters and specific surface areas. </p> <p> The adsorption (removal) capacity of these materials was evaluated through the determination of their adsorption isotherms on a residual organics solution, obtained from an activated sludge reactor, that operated with Phenol as a substrate. </p> <p> On the basis of these isotherms Filtrasorb 400, an activated Carbon with 3SA0 average pore diameter and 1200 m2/g specific surface area, was selected as the best adsorbant. Subsequently a fluidized bed biological reactor was used to study the direct adsorption of the residual organics produced by the biofilms on the Filtrasorb 400 particles supporting the growth. A phenol solution was fed to the reactor and different Oxygen to Phenol ratios were applied. </p> <p> The adsorption of the residual organic molecules generated by the biological growth in a fluidized bed biological reactor proved feasible and independent of the Oxygen to Phenol ratio applied. The Phenol removal efficiency of the reactor was determined by the Oxygen supplied. The removal reached 100% whenever residual Oxygen was present in the effluent of the reactor (no Oxygen limitation). </p> <p> Specific reaction rates higher than the ones reported in the literature were observed. </p> <p> The removal of the residual organics resulted in a stable effluent pH. </p> <p>The monitoring of the height of the expanded bed that biological growth is a parameter that can be used to monitor the total volume of biological films in the reactor. A volume yield factor can also be calculated. </p> / Thesis / Master of Engineering (MEngr)