Fermentation brines from Spanish style green table olives processing: treatment alternatives previous to recycling or recovery operations

Abstract

BACKGROUND Fermentation brine from Spanish style green table olives processing (FTOP) is characterized by very high conductivity (around 88 mS cm(-1)), high values of suspended solids (near 1300 mg L-1), chemical oxygen demand (around 17 900 mg L-1) and total phenols (1000 mg L-1). In this work, fermentation brines have been exhaustively characterized and pH adjustment-sedimentation, coagulation-flocculation-sedimentation and adsorption with activated carbon have been evaluated.

RESULTS AND CONCLUSIONS The pretreatment selection will depend on the final FTOP management. If no polyphenols elimination is required in view of a further recovery, the best pretreatment is pH adjustment to 9 plus sedimentation. The removal efficiencies achieved were 33.1% suspended solids, 82.5% turbidity and only 10.4% of polyphenols. However, if the final FTOP treatment was biological, the best pretreatment is adsorption with powder active carbon, because this pretreatment implies the maximum reduction of phenols in FTOP, which inhibit microorganism activity in the biological process. The maximum total phenols removal efficiency was 96% with 8 g L-1 of BM8 powder activated carbon (21% soluble COD).