PVDF capillary membranes for olive mill wastewater treatment by direct contact membrane distillation

Tests of Direct Contact Membrane Distillation (DCMD) were carried out on Olive Mill Wastewater (OMW) using five different PVDF capillary membranes [1]. The membranes were asymmetric and were characterized/tested in a lab set-up with the aim of identifying the most suitable one in terms of fouling tendency, rejection of polyphenols and quantity of produced distillate. The membrane performances were studied varying the feed temperature: at 50°C, the distillate fluxes ranged from 4.3 kg/m2h to 10.7 kg/m2h while the polyphenol content in the permeate varied between 10 ppm and 45 ppm, corresponding to a rejection of 99.6% and 98.2%, respectively. For all tested membranes, it was obtained a significant concentration of the feed (the feed volume was reduced up to 99%).