Olive mill wastewaters (OMWs) represent a serious environmental problem of Mediterranean countries where the olive processing in an important and traditional industry since ancient times. The detrimental environmental impact of OMW is related to its highly polluting organic load arising from polyphenolic compounds with low biodegradability. The powerful pollutants prohibit OMWs to be directly discharged. Several treatment procedures including physical, chemical, biological or combined technologies have been propose to reduce undesirable properties of OMWs prior to disposal [1]. Recently, in relation to the major interest for the natural compounds with biological activities, researches have been also oriented to the recovery of polyphenols as high value compounds, transforming OMWs from effluents to raw material with high potential economic value. Indeed, several studies have shown excellent biological properties such as antioxidant, free radical scavenging, antimicrobial and anticarcinogenic activities of the biophenols of OMWs [2]. These compounds are usually synthesized by chemical methods that are responsible of their high price. Consequently, methods to concentrate and purify polyphenols from OMWs have become a subject of dramatically increased interest in the last several decades. Application of membrane technologies to recovery of antioxidants from OMWs is of interest due to their several advantages (mainly low energy consumption, no additive requirements and no phase change) in comparison with other technologies such as solvent extraction, supercritical fluid extraction and chromatographic separation [3]. This research was undertaken in order to evaluate the influence of nominal molecular weight cut-off, membrane material and operating conditions on the selectivity of ultrafiltration (UF) and nanofiltration (NF) membranes towards biophenols contained in OMWs produced according to a 3-phase centrifugation process. The performance of the investigated membranes was also evaluated in terms of permeate flux and membrane fouling. Finally, combinations of different membrane processes were analysed for the fractionation of OMWs into by-products in order to develop a natural product suitable to be used as health food supplement and natural food antioxidant. The results obtained in the present study supply useful indications for the development of a proper system design aimed at: 1) the optimization of the selective separation of valuable compounds; 2) the reduction of the polluting load of OMWs; 3) the recovery of significant amount of water with good characteristics both for recycling and agricultural irrigation.
Recovery of biophenols from olive mill wastewaters by integrated membrane processes
A Cassano;C Conidi;L Giorno;E Drioli
2011
Abstract
Olive mill wastewaters (OMWs) represent a serious environmental problem of Mediterranean countries where the olive processing in an important and traditional industry since ancient times. The detrimental environmental impact of OMW is related to its highly polluting organic load arising from polyphenolic compounds with low biodegradability. The powerful pollutants prohibit OMWs to be directly discharged. Several treatment procedures including physical, chemical, biological or combined technologies have been propose to reduce undesirable properties of OMWs prior to disposal [1]. Recently, in relation to the major interest for the natural compounds with biological activities, researches have been also oriented to the recovery of polyphenols as high value compounds, transforming OMWs from effluents to raw material with high potential economic value. Indeed, several studies have shown excellent biological properties such as antioxidant, free radical scavenging, antimicrobial and anticarcinogenic activities of the biophenols of OMWs [2]. These compounds are usually synthesized by chemical methods that are responsible of their high price. Consequently, methods to concentrate and purify polyphenols from OMWs have become a subject of dramatically increased interest in the last several decades. Application of membrane technologies to recovery of antioxidants from OMWs is of interest due to their several advantages (mainly low energy consumption, no additive requirements and no phase change) in comparison with other technologies such as solvent extraction, supercritical fluid extraction and chromatographic separation [3]. This research was undertaken in order to evaluate the influence of nominal molecular weight cut-off, membrane material and operating conditions on the selectivity of ultrafiltration (UF) and nanofiltration (NF) membranes towards biophenols contained in OMWs produced according to a 3-phase centrifugation process. The performance of the investigated membranes was also evaluated in terms of permeate flux and membrane fouling. Finally, combinations of different membrane processes were analysed for the fractionation of OMWs into by-products in order to develop a natural product suitable to be used as health food supplement and natural food antioxidant. The results obtained in the present study supply useful indications for the development of a proper system design aimed at: 1) the optimization of the selective separation of valuable compounds; 2) the reduction of the polluting load of OMWs; 3) the recovery of significant amount of water with good characteristics both for recycling and agricultural irrigation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
