Two-stage biological treatment of olive mill wastewater with whey as co-substrate.

摘要

Performance of a 2-stage bioreactor for treating olive oil mills effluents, which are rich in phenols and organic matter, is described. Whey was added as a co-substrate during aerobic digestion of effluents by Candida tropicalis (1st stage), followed by anaerobic digestion (2nd stage). Aerobic digestion degraded just over half (54%) of the phenol present in effluents, and anaerobic digestion generated a biogas containing 68-75% methane (biogas production rate of the system = 1.25 lbiogas lreactor-1 day-1). The system achieved a total chemical oxygen demand reduction of >93% (83 and 62% reduction in anaerobic and aerobic digestion, respectively) and performed well up to an organic loading rate of 3.0 kg chemical oxygen demand l-1 day-1.