Combining submerged membrane technology with anaerobic and ...
Combining submerged membrane technology with anaerobic and ...
Combining submerged membrane technology with anaerobic and ...
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Permeability (L·m -2·h -1·bar -1 )Tertiary <strong>membrane</strong> filtration of industrial wastewater using granular or flocculent biomass SBRsprocedure. Permeability gradually decreased until the subsequent cleaning. These resultsare different from those reported by Li et al. (2005), who compared two <strong>submerged</strong> MBRs<strong>with</strong> flocculent <strong>and</strong> granular sludge. Nevertheless, in that study, the granular sludge wascultivated from <strong>anaerobic</strong> granular sludge, <strong>and</strong> the bioreactors were inoculated directly.400350Period IIIIIIVV300250200150100500115 140 165 190 215 240 265 290 315 340Time (d)Figure 3.9. Permeability evolution in the F-SBR ( ) <strong>and</strong> G-SBR (•) systems. The greyarea represents period IV, during which the feed was filtered. The observed peaks inpermeability correspond to those days on which chemical recoveries were performed.The permeability values obtained during tertiary filtration were significantly betterthan those obtained previously in a pilot-scale MBR treating municipal wastewater <strong>with</strong> thesame fibre. The permeabilities in the MBR varied between 50 <strong>and</strong> 70 L·m -2·h -1·bar -1 (Artigaet al., 2006). TMP behaviour was similar for both <strong>membrane</strong>s.The objective of period IV was to assess the effect of particulate COD on thepermeability of both filtration systems <strong>and</strong> on SBR performance. During this period, the fedwastewater was firstly centrifuged, <strong>and</strong> the supernatant was filtered later to removeparticulate matter in the influent. During this study, it was assumed that the permeability ofthe systems fed <strong>with</strong> wastewaters <strong>with</strong> low MLTSS values, such as primary treatedwastewaters, would be higher than that of systems fed <strong>with</strong> raw pre-treated water.Nevertheless, the permeability values in both systems during period IV were lower thanthose observed during periods II, III <strong>and</strong> V. Permeability was below 100 L·m-2·h-1·bar-1during this period (grey area in figure 3.9). Membrane fouling in both systems was clearlymore severe during this period because suspended solids were removed from the influent.MLTSS concentration in the wastewater ranged from 0.05 to 0.20 g·L -1 , depending on theCOD concentration. MLVSS represented 75 % of the MLTSS.99
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