Combining submerged membrane technology with anaerobic and ...

Flux (L·m -2·h -1 )Permeability (L·m -2·h -1·bar -1 )Combining UASB and MBR for the treatment of low-strength wastewater at environmental temperaturesab45040035030025020015010050025I II III IV0 50 100 150 200 250 300 350Time (d)I II III IV201510500 50 100 150 200 250 300 350Time (d)Figure 4.4. a) Evolution of permeability (•) and b) flux () during periods I, II, III and IV.Membrane critical flux did not varied significantly during periods I, III and IVincreasing from 19 L·m -2·h -1 during the first period to 20 L·m -2·h -1 in periods III and IV.Nevertheless, measured critical flux during period II increased up to 24 L·m -2·h -1 . The fluxapplied during the operation was always below the critical flux, thus it was expected thatreversible fouling was predominant. However, this effect was only observed during periodII, when permeability was almost fully recovered when a physical cleaning with tap waterwas carried out. On the other hand, two intensive chemical cleanings were performed on123