Fouling mechanisms and primary foulant constituents in reverse osmosis membrane reclamation of a petrochemical secondary effluent

In this study, fouling in the system of reverse osmosis (RO) fed with ultrafiltration prefiltered petrochemical secondary effluent was studied by using a laboratory-scale RO setup. With the micro-analysis of the fouling layer, the residual organic foulants were found to be the primarily responsible elements for the evolution of irreversible fouling. After characterization of the dissolved organic matter in the wastewater with gas chromatograph-mass spectrometer, it had been identified that aromatic compounds and hydrocarbon compounds were the major chemicals. With the help of Fourier transformed infrared spectra, the aromatics were detected to be the predominant organic foulants found on the membrane surface. According to results of electron-dispersive X-ray microanalysis spectrometry, metal cations such as Fe3+ and Mg2+ also contributed to irreversible fouling to some extent. This study identified that reducing adsorption of the organics on the membrane surface is a more effective way or method to control membrane fouling in the reclamation of the secondary effluent.