Anaerobic digestion challenge of raw olive mill wastewater

► The raw olive mill wastewater-OMW was anaerobically digested under stable conditions. ► OMW high energetic potential (>50 kg COD m−3) is directly recoverable into methane. ► Complementary effluents concept promoted microbial adaptation to OMW (100% v/v). ► OMW unbalanced/inhibiting characteristics did not prevent the good hybrid functioning. ► Hybrid also worked in stable conditions under successive shocks of load.