title: Extraction of antioxidants from olive mill wastewater and electro-coagulation of exhausted fraction to reduce its toxicity on anaerobic digestion.
abstract: Liquid-liquid extraction was used in order to recover phenolic compounds from centrifuged olive mill wastewater (OMW), a polluting by-product of olive oil production process, and to reduce their toxicity for a subsequent aerobic or anaerobic digestion. Phenolic compounds were identified in untreated and treated OMW by gas chromatography coupled to mass spectrometry (GC-MS). The experimental results of ethyl acetate extraction showed that the monomers recovery efficiency was over 90%. This pre-treatment resulted in the removal of the major LMM phenolic compounds and a small part of HMM polyphenols. The aerobic treatment of the exhausted OMW fraction removed 78.7% of the soluble COD. In the case of anaerobic digestion at OLR ranged from 1 to 3.5 gCOD l(-1)day(-1), methanisation process exhibited high methane yield as 0.3 l CH4 produced per g COD introduced and high COD removal (80%). However, a disruption of the process was observed when the OLR was increased to 4.5 gCODl(-1)day(-1). A pre-treatment by electro-coagulation resulted in decreasing the toxicity and enhancing the performance of methanisation operated at higher OLR from 4 to 7.5 gCODl(-1)day(-1).
authors.affiliation: Centre de Biotechnologie de Sfax, B.P. K, 3038 Sfax, Tunisia.
authors.forename: Sonia
authors.initials: S
authors.lastname: Khoufi
authors.forename: Fathi
authors.initials: F
authors.lastname: Aloui
authors.forename: Sami
authors.initials: S
authors.lastname: Sayadi
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000737:chemistry* / Q000494:pharmacology; D001421:Bacteria, Anaerobic; D001673:Biodegradation, Environmental; D002849:Chromatography, Gas / Q000379:methods; D004563:Electrochemistry / Q000379:methods*; D004564:Electrocoagulation / Q000379:methods; D004867:Equipment Design; D005419:Flavonoids / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste / Q000032:analysis*; D008970:Molecular Weight; D031658:Olea; D010636:Phenols / Q000032:analysis; D059808:Polyphenols; D012997:Solvents; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000975:Antioxidants; D005419:Flavonoids; D007220:Industrial Waste; D010636:Phenols; D059808:Polyphenols; D012997:Solvents; D014874:Water Pollutants, Chemical