Removal of Organic Compounds from Olive Mill Wastewater by Flotation-Anaerobic-Aerobic Processes and Lime Treatment

Olive oil extraction processes generate two types of residues: pomace and olive oil mill wastewater (OMW). Hence, OMW's direct discharge affects the environment by altering soil quality, pollution of natural water, inhibition of grain germination, and olfactory nuisances. This work aims to contribute to solving the problem generated by olive oil discharge. Indeed, we have proposed the possibility of treating raw wastewater from upstream oil mills by a combined flotation-aerobic- aerobic process followed by precipitation with lime. The physicochemical analysis results showed that the physically and biologically treated samples have a chemical oxygen demand (COD) of 95 g of O-2/L, an acid pH (4.95), the turbidity of 1293 NTU, a polyphenol concentration of 2.02 g/L, and phosphorus of 173.7 mg/L. The proposed strategy using lime treatment reduces 56.8% COD, 92.94% turbidity, 91% polyphenols, and 95.4% phosphorus.