Loading and Stress Effects on Flat Sheet Membrane Bioreactor (FSMBR) Fouling

The objective of the research was to investigate the effects of inducing loading and bacterial stress conditions on the fouling of the membranes. Two paralleled laboratory-scale flat sheet membrane bioreactors (FSMBR) with three Kubota Type 203 flat membrane cartridges in each were set up to treat a synthetic sugar-based industrial wastewater. One reactor served as the control, while the other one served as the experimental reactor. One parameter was varied in the experimental reactor versus the control for each phase. Three stress conditions were employed during the study, including different organic loading rates (OLR phase), high salt concentration (salt phase), and temperature spikes (temperature phase). The synthetic sugar-based wastewater provided a consistent COD strength of approximately 7100 mg/L.Several key parameters were monitored during the study. 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 have an effect on the bacteria in the MBR which impacts on sludge characteristics such as filterability, polysaccharide production, floc size, effluent COD concentration, effluent color, and most importantly the rate of membrane fouling.