Experimental design for optimization of olive mill wastewater final purification with Dowex Marathon C and Amberlite IRA-67 ion exchange resins

The final purification of two-phase olive mill wastewater (OMW-2) by ion exchange (IE) was addressed. This pollutant effluent was previously subjected to Pseudo-Fenton secondary treatment. Consequently, OMW-2 presented high concentrations of chloride, sodium, phenols and iron, which hinder its discharge. Experimental design was used to optimize the IE process. Around 88% removal efficiencies of these pollutants were achieved when initial pH, temperature and flow rate were 5.1, 26.8 °C and 12.1 L h−1, respectively. Finally, 28 L treated water could be accomplished in continuous mode under optimal conditions, complying with standards for reuse in the olive oil production process.