Stress Effects on Fouling of Flat Sheet Membrane Bioreactor Treating Biodegradable Wastewater

Two laboratory-scale flat sheet membrane bioreactors (FSMBR) with three flat sheet membrane cartridges in each were set up to treat a synthetic biodegradable industrial wastewater. Four stress conditions were employed during the study including different organic loading rates (OLR phase), high salt concentration (salt phase), temperature spikes (temperature phase), and mixed liquor suspended solid (MLSS) concentration (MLSS phase). This study investigated the impact of the stress factors on membrane fouling and evaluated the performance of the FSMBR. Under the imposed stress conditions, the experimental reactor had a smaller particle size, higher average effluent COD concentration, and lower sludge filterability. The experimental reactor also fouled at a faster rate than the control reactor. The results showed that imposed stress conditions had an effect on the bacteria in the MBR which impacted sludge characteristics such as filterability, polysaccharide production, floe size, effluent COD concentration, effluent color, and most importantly the rate of membrane fouling.