OXYGEN AIR ENRICHMENT THROUGH DENSE MEMBRANE: APPLICATION TO A BIOFILM REACTOR

A highly permeable composite hollow-fiber membrane developed for air separation was used to develop a biofilm reactor. The composite membrane consists of a porous support layer covered with a thin dense film that is responsible for oxygen enrichment of the permeate stream. Besides the oxygen enrichment capability, dense membranes overcome the major operational problems that occur when using porous membranes for oxygen transfer to biofilm.The biofilm that grows attached to the external membrane surface consumes oxygen for organic load degradation. Air flowrate and oxygen partial pressure inside the fibers were the variables used to adjust oxygen flux and recovery. The biofilm reactor was operated with hydraulic retention times ranging between 1 and 4 hours. High values of organic load removal rate such as 6.5 kg total COD/m3.d (1.6 g/m2.h) were due to oxygen transfer rate as high as 107 kg/m3.day (26.5 g/m2.h).The high values of organic load removal rates, with improved oxygen transfer efficiency, indicates that the MABR process is a promising and compact alternative to the conventional activated sludge process and that the membrane selected is suitable for the process development.