Clarification of high-added value products from olive mill wastewater

The objective of the current study is to investigate the clarification of two high-added value products (pectin containing solution and phenol containing beverage) recovered from olive mill wastewater. For this purpose, both liquids were processed with four types of ultrafiltration (100, 25, 10 and 2 kDa) and one nanofiltration membranes under optimum transmembrane pressure. Retention coefficients and performance parameters were monitored for each experiment. The membranes of 25 and 100 kDa showed very satisfying results with regard to the concentration of pectin solutions as they were able to separate it from cations and phenols. The membrane of 25 kDa was also able to partially remove the heavier fragments of hydroxycinnamic acid derivatives and flavonols, and simultaneously to sustain the antioxidant properties of the phenol containing beverage in the permeate stream. Finally, nanofiltration clarified the beverage from cations that passed in the permeate stream, but this process resulted in loss of antioxidant compounds, too. (C) 2010 Elsevier Ltd. All rights reserved.