Techno-economic assessment of a biorefinery plant for extracted olive pomace valorization

Abstract

This study reports on a new integrated valorization alternative for extracted olive pomace (EOP) by recovering polyphenols as high-value compounds and the subsequent anaerobic digestion of the remaining dephenolized fraction for energy production. The average polyphenol extraction rate was 22.10 kg GAE t−1 EOP and the subsequent optimum methane production from the remaining dephenolized fraction (278 L CH4 kg VS−1 d−1) occurred at organic loading rate (OLR) 2.48 g VS L−1 d−1 and 24 d hydraulic retention time (HRT). The study also reports on the preliminary economic feasibility study and the sensitivity analysis to valorize 1,500 t EOP y−1 under biorefinery concept. The calculated net present value (NPV) and internal return rate (IRR) were €1,996,856 and 58 %, respectively. The sensitivity analysis concluded that the minimum sales volume of hydroxytyrosol (HT) extract and the sale price per mass are by far the most significant factors that might influence the overall economic feasibility of the proposed EOP valorization plant.