title: Detoxification of olive mill wastewater by electrocoagulation and sedimentation processes.
abstract: Olive mill wastewater (OMW) is characterised by its high suspended solids content (SS), high turbidity (NTU), chemical oxygen demand (COD) concentration up to 100 gl(-1) and toxic phenolic compounds concentration up to 10 gl(-1). This study examined the effect of a physico-electrochemical method to detoxify olive mill wastewater prior an anaerobic biotreatment process. The proposed pre-treatment process consisted in a preliminary electrocoagulation step in which most phenolic compounds were polymerised, followed by a sedimentation step. The BOD(5)/COD ratio of the electrocoagulated OMW increased from 0.33, initial value, to 0.58. Furthermore, the sedimentation step yielded the removal of 76.2%, 75% and 71% of phenolic compounds, turbidity and suspended solid, respectively, after 3 days of plain settling. The combination of electrocoagulation and sedimentation allowed a COD reduction and decoloration of about 43% and 90%, respectively. This pre-treatment decreases the inhibition of Vibrio fisheri luminescence by 66.4%. Continuous anaerobic biomethanization experiments conducted in parallel with raw OMW and electrocoagulated OMW before and after sedimentation at a loading rate of 6g COD l(-1)day(-1), proved that the final pre-treated OMW was bioconverted into methane at high yield while raw OMW was very toxic to anaerobic microorganisms.
authors.affiliation: Laboratoire des Bio-procédés, Centre de Biotechnologie de Sfax, BP: K, 3038 Sfax, Tunisia.
authors.forename: Sonia
authors.initials: S
authors.lastname: Khoufi
authors.forename: Firas
authors.initials: F
authors.lastname: Feki
authors.forename: Sami
authors.initials: S
authors.lastname: Sayadi
mesh_terms: D048908:Aliivibrio fischeri / Q000378:metabolism; D000693:Anaerobiosis; D003116:Color; D004564:Electrocoagulation / Q000379:methods*; D052918:Environmental Restoration and Remediation / Q000379:methods*; D007220:Industrial Waste; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010938:Plant Oils / Q000737:chemistry* / Q000378:metabolism / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000378:metabolism / Q000633:toxicity*
chemical_list: D007220:Industrial Waste; D000069463:Olive Oil; D010938:Plant Oils; D014874:Water Pollutants, Chemical