Complete treatment of olive mill wastewaters by electrooxidation

Abstract Laboratory scale electrochemical experiments on a olive mill wastewater (OMW) were performed to obtain discharge quality which meets the regulations requirement without any pre- or additional treatment. The process has been examined through the dependence of chemical oxygen demand (COD), oil-grease, phenol and turbidity on electrolysis duration. The influence of current density (25, 45, 65, 75, 85, 105, 135 mA cm−2), sodium chloride concentration (1, 2, 3, 5 M), recirculation rate of OMW (1.1, 4.6, 7.9 cm3 s−1) and temperature (7, 20, 40 °C) on the rate of pollutants abatement and the response of the system and specific energy consumption were evaluated. Based on the results obtained from laboratory experiments, the removal rates of organics increased with the increase of applied current density, sodium chloride concentration, recirculation rate and temperature. The results also indicated that specific energy consumption (SEC) ranged between 5.35 and 27.02 kWh (kg COD)−1 decreased with increasing NaCl concentration, recirculation rate and temperature whereas it increased with increasing current density. The initial COD concentration of 41,000 mg L−1 was reduced to 167 mg L−1 (corresponding to 99.6% removal) which complies with legal requirements while almost complete conversion of phenol, 99.85% turbidity removal, 99.54% oil-grease removal were achieved with the running cost of 0.88€ (kg COD)−1 after 7 h electrolysis at the conditions of 135 mA cm−2, 2 M NaCl, 7.9 cm3 s−1, 40 °C.

[1]  M. Panizza,et al.  Olive mill wastewater treatment by anodic oxidation with parallel plate electrodes. , 2006, Water research.

[2]  K. Palanivelu,et al.  Electrochemical treatment of industrial wastewater. , 2004, Journal of hazardous materials.

[3]  Nicolas Kalogerakis,et al.  Electrochemical oxidation of olive oil mill wastewaters. , 2005, Water research.

[4]  Ji-Dong Gu,et al.  Reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes. , 2005, Water research.

[5]  Juu‐En Chang,et al.  Electrochemical oxidation pretreatment of refractory organic pollutants , 1997 .

[6]  G. Saracco,et al.  Electrochemical oxidation of organic pollutants at low electrolyte concentrations , 2000 .

[7]  Juu-En Chang,et al.  Indirect oxidation effect in electrochemical oxidation treatment of landfill leachate , 1995 .

[8]  Eung-Bai Shin,et al.  Effects of Cl-based chemical coagulants on electrochemical oxidation of textile wastewater , 2003 .

[9]  M. Karpuzcu,et al.  Olive oil mill wastewater treatment by means of electro-coagulation , 2004 .

[10]  N. Adhoum,et al.  Decolourization and removal of phenolic compounds from olive mill wastewater by electrocoagulation , 2004 .

[11]  Pablo Cañizares,et al.  Treatment of Fenton-refractory olive oil mill wastes by electrochemical oxidation with boron-doped diamond anodes , 2006 .

[12]  K. Lasaridi,et al.  Combined bioremediation and advanced oxidation of green table olive processing wastewater , 2005 .

[13]  Sami Sayadi,et al.  Treatment of olive oil mill wastewater by combined process electro-Fenton reaction and anaerobic digestion. , 2006, Water research.

[14]  C. Comninellis,et al.  Anodic oxidation of phenol in the presence of NaCl for wastewater treatment , 1995 .

[15]  A. Vlyssides,et al.  Olive oil wastewater treatment with the use of an electrolysis system , 1997 .

[16]  B. Yazıcı,et al.  The effect of pH, temperature and concentration on electrooxidation of phenol. , 2005, Journal of hazardous materials.

[17]  B. Vodopivec,et al.  Electrochemical treatment of olive oil mill wastewater. , 2001, Annali di chimica.

[18]  Yusuf Yavuz,et al.  Electrochemical oxidation of phenol in a parallel plate reactor using ruthenium mixed metal oxide electrode. , 2006, Journal of hazardous materials.

[19]  S. Sayadi,et al.  Application of electro-Fenton oxidation for the detoxification of olive mill wastewater phenolic compounds. , 2004, Water science and technology : a journal of the International Association on Water Pollution Research.

[20]  Nina Dimcheva,et al.  Electrooxidation of phenol by catalase immobilized on graphite electrodes. , 2001, Bioelectrochemistry.

[21]  A. Zorpas,et al.  Electrochemical oxidation of noncyanide strippers wastes , 1999 .

[22]  V. Montiel,et al.  Influence of chloride ion on electrochemical degradation of phenol in alkaline medium using bismuth doped and pure PbO2 anodes. , 2001, Water research.