Optimization and fouling mechanism of a thermophile submerged MBR (TSMBR) pilot plant for wastewater treatment in a paper mill

Key results are inter alia a sub-critical flux of below 10 L m−2 h−1 is recommended for long-time durability of the membrane for minimizing the irreversible fouling and the permeability decrease. A chemical cleaning does not change the critical flux, but improves the permeability of the membrane significantly. The TSMBR suffered from increasing fouling at a cross-flow-aeration of below 0.6 m3 m−2 h−1 and a concentration of suspended solids of above 14 g L−1. A stable process and cleaning could only be ensured by a F/M ratio of below 0.4 gCOD gMLSS−1 d−1. Higher values result in an increased cake layer formation and intensive foaming.