DESIGN OPTIMIZATION OF A POLYMERIC NANOFILTRATION MEMBRANE FOR OLIVE MILL WASTEWATER VALORIZATION PLUS PURIFICATION

The core of the present work was to model and optimize an environmentally friendly nanofiltration (NF) treatment process for two-phase olive mill wastewater (OMW) valorization throughout concentration and recovery of its phenolic fraction and the obtention of a purified permeate stream. A factorial design was used for the optimization of the process. Results were interpreted by the response surface methodology. A statistical multifactorial analysis was performed in order to quantify all the potential complex conjugated effects of the input parameters in the NF process. The process was subsequently modelled by means of a second-grade quadratic fitting model equation. Finally, the parametric quality standards that permit to reuse the purified stream for irrigation or discharge in-site reuse purposes were checked. To the author’s knowledge, no previous work on the optimization and statistical modelling of membrane processes for OMW purification and valorization can be found up to the present. The optimized data are very relevant for the feasible scale-up of the proposed process, since the NF membrane was highly efficient at ambient temperature conditions and raw effluent pH. The optimized conditions provided a permeate stream that could be reused for irrigation purposes and a retantate stream concentrated in total phenolic content of minimum 1315.7 mg/L.