Treatment of olive oil mill wastewater by a pulsed high‐voltage discharge process; process optimization and combination with Fe +2 and H 2 O 2

BACKGROUND Olive oil mill wastewaters ( OOMW ) have caused major environmental problems because of the high organic load, high total suspended solids, high inert chemical oxygen demand ( COD ), low pH , a characteristic odour, its dark colour and toxicity to plants. A pulsed high‐voltage discharge ( PHVD ) process was developed as a novel alternative to advanced oxidation processes for effective treatment of OOMW . RESULTS The ability of a PHVD process, after acid cracking, to treat OOMW , was investigated . For a PHVD treatment time of 60 min the chemical oxygen demand ( COD ), total organic carbon ( TOC ), phenol, and colour removal efficiencies were 21, 31, 23, and 32%, respectively. Following the addition of 63 mmol L −1 H 2 O 2 , the COD , TOC , phenol, and colour removal efficiencies reached 72, 55, 74, and 82%, respectively, for the same treatment time. When 0.37 mmol L −1 Fe 2+ (but no H 2 O 2 ) was added, the COD , TOC , phenol, and colour removal efficiencies were 74, 54, 79, and 72%, respectively . CONCLUSION PHVD can be used to effectively treat OOMW , using a combination of physical and chemical effects initiated by the electrical discharge into the water. © 2014 Society of Chemical Industry