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The disposal of wastewater resulting from olive oil production (olive mill wastewater, OMW) is a major issue for olive oil producers. This wastewater is among the most polluting due to the very high concentration of organic substances and the presence of hardly degradable phenolic compounds. The systems proposed for OMW treatment are essentially based either on conventional chemical-physical, biological and thermal processes, or on membrane processes. With respect to conventional methods, membrane processes allow to separate different species without the use of chemicals or heat. This work deals with the use of the integrated pressure-driven membrane processes for the treatment of OMW. They consist of a first stage (microfiltration, MF) in which a porous multichannel ceramic membrane retains suspended materials and produces a clarified permeate for a second stage (reverse osmosis, RO), in order to separate (and concentrate) dissolved substances from water. Laboratory scale experiments with different small flat sheet RO membranes were first carried out in order to select the most appropriate one for the successive bench scale tests with a spiral wound module having a large membrane surface. The aim of this test was to concentrate the dissolved substances and to produce water with low salinity, chemical oxygen demand (COD), and reduced phytotoxicity due to a low content of phenolic compounds. The trend of the permeate flux and membrane retention as a function of the volume concentration ratio was investigated. The influence of OMW origin and its aging on the membrane performance was also studied.

Experimental trials are usually needed to integrate information reported on data sheets in order to properly drive membrane choice. It results in data-sets where each membrane is characterised by several performance descriptors. Multivariate data-mining (i.e. chemometrics) effectiveness in analysing such data-sets has been demonstrated through the comparison of seven commercial membranes. Each membrane was represented as an object described by 15 features got from trials with different single-component test solutions. Tree cluster analysis based on Ward amalgamation method was employed for multivariate data mining. The algorithm progressively grouped the membranes in clusters, adopting the Euclidean distance in the 15-dimensional feature space as a measure of similarity. Thus, a graphical output consisting into a similarity tree representing the membrane taxonomy was obtained. A restricted number of membranes, selected as representatives of each identified cluster, underwent to further experiments...

Electrodialysis (ED) is applied in different fields of industry (Strathmann 2010). It has found wide application in water and wastewater treatment, stabilization of wine, whey demineralization and also for recovery of valuable components associated with the depuration of wastewater. New treatment processes can be designed by integration with other membrane processes as well as nanofiltration an reverse osmosis. Aim of the work is the study of electrodialysis process with some model salt solutions and the attempt to apply it to some industrial wastewater. Electrodialysis tests were mainly performed using model solutions containing nitrates, ammonia or metals. Few tests have been carried out on some real effluents as coke oven wastewater or olive mill wastewater, which were treated in the electrodialysis plant after reverse osmosis concentration. In the present paper some results about the ED treatment of solution containing high copper concentration will be shown.

Gas–liquid membrane contactors were applied to remove carbon dioxide from a gas stream by using an aqueous monoethanolamine (MEA) solution as absorbent. Various modules composed by different numbers of commercial polypropylene capillary membranes were constructed and tested in a laboratory-scale plant fed with a N2–CO2 gas mixture. Attention was especially focused on the CO2 removal efficiency of the different membrane modules when gas flow rate was increased from 5 up to 360 L/h. A mathematical model was developed to simulate the absorption process in order to predict gas removal efficiency from the knowledge of the system physical parameters. The overall membrane mass transfer coefficient kM was determined and used to compare experimental and predicted removal efficiencies. A good agreement between the developed model and experimental results was found.

Membrane bioreactors have been extensively studied for the treatment of domestic wastewater. In this paper we describe the application of membrane bioreactors for the depuration of non-civil wastewater coming from the washing of mineral oil storage tanks. Microfiltration hollow-fibre membranes were submerged in the bioreactor where the biomass used the hydrocarbon as a substrate. The performance of the submerged membrane bioreactor was analysed in terms of COD and hydrocarbon removal during different experiments that showed the high efficiency of the system. Particular care was taken in carrying out the operations in the sub-critical flux region. The reactor performance was very high, with removal efficiencies ranging between 93% and 97%, also when the concentration of hydrocarbon was very high. Moreover, the hydraulic retention times used in this work were lower compared to those used in an activated sludge process. Some kinetic parameters for the COD and the hydrocarbon removal were assessed.

Producción Científica, Structural and surface properties of two commercial polysulfone ultrafiltration membranes have been evaluated by different techniques. Pore size distributions have been determined by Liquid–Liquid Displacement Porosimetry (LLDP) as well as by image analysis performed onto Field Emission Scanning Electron Microscopy (FESEM) images of the membrane surfaces. Fourier TransformInfrared Spectroscopy (FTIR) has been used to investigate membrane composition, and in particular, to obtain proper information on the presence of an additive within the membrane structure. Porosimetric results obtained by the two independent techniques compared reasonably well and the Molecular Weight Cut Off (MWCO) of the two membranes estimated from LLDP pore size distribution was found to be in good agreement with the nominal values given by manufacturers., Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA302U13)

Although water is essential for human survival and progress, it is distributed very unevenly and with a different purity over the surface of the earth. A variety of contaminants can be present in raw water, depending on its origin. The size of these contaminants ranges from the micrometer (e.g. bacteria) to the tenths of a nanometer order (ions). Membrane processes like microfiltration, ultrafiltration, nanofiltration and reverse osmosis could be a solution for an advanced physical treatment of water for drinking purposes as well as for agroindustrial sectors. Many applications are well assessed and are expanding very quickly; however, to obtain an ever-growing performance, it is necessary to prepare membranes with tailored structure and transport properties. Characterisation methods play also a role of paramount importance for the selection of the more appropriate membrane for the above-mentioned applications. In this work the main membrane preparation techniques and characterisation methods will be reviewed and discussed.