A new attempt to treat and reuse the industrial laundry wastewater using biological treatment followed by advanced oxidation processes (AOPs) and membrane separation is presented. Three various configurations of the hybrid systems were investigated: (1) biological treatment in a Moving Bed Biofilm Reactor (MBBR) – photocatalysis with suspended TiO2 P25, enhanced with in situ generated O3 – ultrafiltration (UF) – nanofiltration (NF); (2) biological treatment in MBBR– photocatalysis with immobilized TiO2 P25, enhanced with in situ generated O3 – UF - NF; (3) biological treatment in MBBR – photolysis/ozonation (with in situ generated O3) – UF – NF. For comparison purpose the wastewater was additionally treated in the MBBR – UF – NF mode (4). Application of AOPs contributed to the UF membrane fouling mitigation during treatment of the biologically pretreated laundry wastewater. The highest improvement of the UF permeate flux was found in case of the MBBR effluent treated with application of the immobilized TiO2 bed which was attributed to the highest efficiency of mineralization observed for that system. Since the applied wastewater contained significant amounts of inorganic ions, mainly Na+ and Cl-, the NF as the final polishing step was proposed. The quality of NF permeate was independent on the AOP mode applied and, moreover, significantly higher than the quality of water currently used in the laundry. It was concluded that the NF permeate could be recycled to any stage of the laundry system. Taking into consideration that application of TiO2 increases the overall treatment costs and that although the O3/UV pretreatment is less efficient than photocatalysis, it still allows to improve the UF permeate flux for ca. 35% compared to the direct UF of the MBBR effluent, the MBBR – UV/O3 – UF – NF system was proposed as the most beneficial configuration for the treatment and reuse of the industrial laundry wastewater
