Polyphenols concentration's effect on the biogas production by wastes derived from olive oil production

Olive oil production gives two high polluting refuses: the semisolid Olive Pomace (OP) and the liquid Olive Mill Wastewater (OMWW). These refuses actually present either from technology or from social point of views high disposal problems. An approach able to solve these problems seems to be the Anaerobic Digestion (AD), which permits to obtain a stabilized sludge and a biogas with high content of methane. OP and OMWW contain some recalcitrant constituents as lignocelluloses and polyphenols which are able to inhibit the AD. At this aim, in the present work some physical and chemical pretreatments were accomplished by AD fermentation tests. After each pretreatment the polyphenols concentration were evaluated against nopretreated mixture. The best results were obtained with salts additions (FeCl3 and CaCO3) which make the simultaneous actions of reducing the polyphenols concentration by flocculation phenomena and increasing the biodegradation of recalcitrant ligno-cellulosic materials.