Combining submerged membrane technology with anaerobic and ...

Chapter 3operated with high MLTSS concentrations compared with typical values reported for TMF(Citulsky et al., 2009), in the range of mg·L -1 . MLVSS concentrations in the tertiary filtrationchambers were between 0.3 - 6.0 and 0.3 - 6.8 g·L -1 (figure 3.7) as a result of theoperating strategies of the filtration systems. The TMF chambers were punctually purgedin order to maintain similar MLVSS and SRT values (between 20 and 30 d).As expected, the sludge settling properties were significantly different for the twosystems. The differences between the settling properties of the biomasses developed inboth reactors were remarkable. In the F-SBR, the SVI values were between 50 and 300ml·g -1 , while in the G-SBR, the SVI values ranged from 30 to 100 ml·g -1 . Moreover, theSSR were 0.7 m·h -1 and 9.7 m·h -1 for the flocculent and granular sludge, respectively.Microscopic observation shows remarkable differences not only between biomass inboth reactors but also between biomass into filtration chambers. As can be observed infigure 3.8, microbiological aggregates in granular system are substantially bigger.abaFigure 3.8. Microscopy observation of flocculent (a) and granular (b) biomass in TMFchambers.3.4.2. Tertiary membrane filtration3.4.2.1. Membrane performancesOne of the main objectives of this study was to determine if the effluent from agranular biomass bioreactor caused less membrane fouling than that from a flocculentbioreactor. Nevertheless, permeability values between 160 and 75 L·m -2·h -1·bar -1 wereobserved in the two TMF systems at a flux of 10 L·m -2·h -1 , indicating that TMF of botheffluents produced similar results. Moreover, the permeability evolutions of the twomembrane modules were similar (figure 3.9). For both membranes, the maximumpermeability value was achieved after performing either a physical or a chemical cleaningb98