The innovative Osmotic Membrane Bioreactor (OMBR) for reuse of wastewater

摘要

An innovative osmotic membrane bioreactor (OMBR) is currently under development for thenreclamation of wastewater, which combines activated sludge treatment and forward osmosis (FO)nmembrane separation with a RO post-treatment. The research focus is FO membrane fouling andnperformance using different activated sludge investigated both at laboratory scale (membrane area ofn112 cm2) and at on-site bench scale (flat sheet membrane area of 0.1m2). FO performance onnlaboratory-scale (i) increased with temperature due to a decrease in viscosity and (ii) was independentnof the type of activated sludge. Draw solution leakage increased with temperature and varied forndifferent activated sludge. FO performance on bench-scale (i) increased with osmotic driving force,n(ii) depended on the membrane orientation due to internal concentration polarization and (iii) wasninvariant to feed flow decrease and air injection at the feed and draw side. Draw solution leakage couldnnot be evaluated on bench-scale due to experimental limitation. Membrane fouling was not found onnlaboratory scale and bench-scale, however, partially reversible fouling was found on laboratory scale fornFO membranes facing the draw solution. Economic assessment indicated a minimum flux ofn15 L.mu00022hu00021 at 0.5M NaCl for OMBR-RO to be cost effective, depending on the FO membrane price.