Concentration of olive mill wastewater by membrane distillation for polyphenols recovery

The possibility of olive mill wastewaters (OMW) treatment and concentration by membrane distillation has been investigated. The objective is to obtain pure water and a concentrate containing high amounts of polyphenols, which can be extracted later. Two types of commercial membranes, polytetrafluoroethylene (TF200) and polyvinilydene fluoride (GVHP), were tested and the effects of membrane parameters on direct contact membrane distillation (DCMD) performance (i.e. permeate flux and polyphenols retention) were studied. The effects of different DCMD operating parameters were also investigated. The obtained results demonstrated the efficiency of DCMD for OMW treatment and concentration. The membrane TF200 showed a better separation coefficient (99%) after 9 h of DCMD operation than the membrane GVHP (89%) and the corresponding OMW concentration factor was found to be 1.72 for the membrane TF200, whereas it was only 1.4 for the GVHP membrane after 9 h operating time.

Membrane distillation (MD) can be used successfully for olive mill wastewaters (OMW) treatment and concentration. Microporous hydrophobic membranes, polyvinylidene fluoride and polytetrafluoroethylene, were applied using direct contact membrane distillation (DCMD). It was found that the DCMD permeate flux is higher for the membrane TF200 than that of the membrane GVHP having greater thickness. Higher permeate flux decline was observed when using the membrane TF200. Additional experiments are clearly needed to enhance both the permeate flux and the concentration factor during the concentration of OMW by MD.