Purification of oily wastewater by hybrid UF/MD

Investigations on the treatment of oily wastewater by a combination of ultr afiltration (UF) and membrane distillation (MD) as a final purification met hod have been performed. A tubular UF module equipped with polyvinylidene f luoride (PVDF) membranes and a capillary MD module with polypropylene membr anes were tested using a typical bilge water collected from a harbour witho ut pretreatment. The permeate obtained from the UF process generally contai ns less than 5 ppm of oil. A further purification of the UF permeate by mem brane distillation results in a complete removal of oil from wastewater and a very high reduction of the total organic carbon (99.5%) and total dissol ved solids (99.9%). (C) 2001 Elsevier Science Ltd. All rights reserved.