In this work, PVDF homopolymer was blended with PVDF-co-HFP copolymer and studied in terms of morphology, porosity, pore size, hydrophobicity, permeability, and mechanical properties. Different solvents, namely N-Methyl-2 pyrrolidone (NMP), Tetrahydrofuran (THF), and Dimethylformamide (DMF) solvents, were used to fabricate blended PVDF flat sheet membranes without the introduction of any pore forming agent, through a non-solvent induced phase separation (NIPS) technique. Furthermore, the performance of the fabricated membranes was investigated for pressure and thermal driven applications. The porosity of the membranes was slightly increased with the increase in the overall content of PVDF and by the inclusion of PVDF copolymer. Total PVDF content, copolymer content, and mixed-solvent have a positive effect on mechanical properties. The addition of copolymer increased the hydrophobicity when the total PVDF content was 20%. At 25% and with the inclusion of mixed-solvent, the hydrophobicity was adversely affected. The permeability of the membranes increased with the increase in the overall content of PVDF. Mixed-solvents significantly improved permeability.

Membrane bioreactors (MBRs) represent the best available technology for municipal and wastewater treatment, as confirmed by the number of wastewater treatment plants based on MBRs in operation worldwide. However, MBRs are not able to effectively reject some substances, like low molecular weight organic compounds found in wastewaters. Therefore, further improvements are needed. In this respect, coupling MBRs with high-retention membrane processes, like reverse osmosis (RO) and membrane distillation (MD), was investigated in the past years. In this paper, the main MBR features and their commercial development are presented. Their performance when coupled with RO and with MD units is discussed, as well as limitations toward a large-scale implementation, with particular emphasis on the further research needed in the field. Finally, MBR-RO and MBR-MD integrated systems are compared in terms of the most significant parameters. Actions to take in order to overcome linked issues are also proposed.