Sequential anaerobic/aerobic biological treatment of olive mill wastewater and municipal wastewater

This work investigated the efficiency of the combined anaerobic/aerobic biological co-treatment of olive mill wastewater and primary municipal wastewater. A laboratory-scale (6.5 L) upflow anaerobic sludge bed reactor received a mixture of olive mill wastewater and primary municipal wastewater at a loading rate ranging between 3 and 7 kg chemical oxygen demand (COD) m -3 day -1 . The input COD concentration ranged between 1800 and 4400 mg L -1 . The anaerobic reactor was operated at mesophilic conditions (35 °C). The effluent organic load was between 400 and 600 mg COD L -1 , while the suspended solids removal efficiency varied between 75 and 95%. Average biogas production ranged between 3 and 4 L g -1 COD removed. The anaerobic reactor effluent was further treated in a laboratory-scale activated sludge treatment plant. Aerobic treatment reduced the organic load even further to 85-175 mg COD L -1 . However, the final effluent still retained a significant level of colour. Removal of colour was possible by ozonation or coagulation. Finally, the treated effluent was non-ecotoxic, as indicated by the Daphnia magna toxicity test. This treatment method showed that it is feasible to treat olive mill wastewater in a municipal wastewater treatment plant by means of a high-rate anaerobic reactor located between the primary clarifier and the aeration tank.

[1]  Jules B. van Lier,et al.  Appropriate technologies for effective management of industrial and domestic waste waters : The decentralised approach , 1999 .

[2]  L. Bertin,et al.  Anaerobic digestion of olive mill wastewaters in biofilm reactors packed with granular activated carbon and "Manville" silica beads. , 2004, Water research.

[3]  J. Beltrán-Heredia,et al.  Improvement of the anaerobic biodegradation of olive mill wastewaters by prior ozonation pretreatment , 1997 .

[4]  J. Hoigne,et al.  Determination of ozone in water by the indigo method , 1981 .

[5]  L. Torrisi,et al.  Integrated treatment of olive oil mill effluents: Effect of chemical and physical pretreatment on anaerobic treatability , 1999 .

[6]  Irini Angelidaki,et al.  Modelling anaerobic codigestion of manure with olive oil mill effluent , 1997 .

[7]  Irini Angelidaki,et al.  Codigestion of olive oil mill wastewaters with manure, household waste or sewage sludge , 1997 .

[8]  E. Sánchez,et al.  Comparative effect of different aerobic pretreatments on the kinetics and macroenergetic parameters of anaerobic digestion of olive mill wastewater in continuous mode , 1998 .

[9]  D. Dalis,et al.  Anaerobic digestion of total raw olive-oil wastewater in a two-stage pilot-plant (up-flow and fixed-bed bioreactors) , 1996 .

[10]  M. Hamdi.  Anaerobic digestion of olive mill wastewaters , 1996 .

[11]  R. Borja,et al.  Effect of aerobic pretreatment with Aspergillus terreus on the anaerobic digestion of olive‐mill wastewater , 1995, Biotechnology and applied biochemistry.

[12]  S. P. Tsonis,et al.  Systematic characterization and chemical treatment of olive oil mill wastewater , 1989 .

[13]  M. Hamdi,et al.  Anaerobic digestion of olive mill wastewaters in fully mixed reactors and in fixed film reactors , 1992 .

[14]  D. Hongve,et al.  Spectrophotometric determination of water colour in hazen units , 1996 .

[15]  L. Bertin,et al.  An aerobic fixed-phase biofilm reactor system for the degradation of the low-molecular weight aromatic compounds occurring in the effluents of anaerobic digestors treating olive mill wastewaters. , 2001, Journal of biotechnology.

[16]  R. Borja,et al.  Anaerobic digestion of black-olive wastewater , 1993 .

[17]  G. Pinto,et al.  Phytotoxicity of Low-Molecular-Weight Phenols from Olive Mill Waste Waters , 2001, Bulletin of environmental contamination and toxicology.

[18]  S. P. Tsonis,et al.  Anaerobic Treatability of Olive Oil Mill Wastewater , 1993 .