Direct Contact and Vacuum Membrane Distillation application for the olive mill wastewater treatment

In this work, Membrane Distillation (MD) in Direct Contact (DCMD) and Vacuum (VMD) configurations were applied for the Olive Mill Wastewater (OMWW) treatment, with the objective to obtain a purified stream to reuse, together with a concentrate rich in polyphenols. The experimental tests were carried out on capillary membranes using a membrane module realized in laboratory and equipped with three commercial polypropylene membranes (membrane pore size: 0.2 μm, thickness: 0.4 mm, inner diameter: 1.8 mm, membrane area: around 30 cm2). The OMWW was frozen for its storage and, before experiments, simple filtration on single and multi-layer tissue were tested, to reduce membrane fouling during the process. The effect on the permeate flux and purity of the feed temperature (30-40-50 °C) for the DCMD and of the feed concentration for the VMD, was investigated.