Journals Proceedings

Abstract

The aim of the study is to evaluate the simultaneous effect of salinity and hydrocarbons on the performances of two parallel Moving Bed-Membrane BioReactor (MB-MBR) systems fed with real saline oily wastewater (slop). Different dilution factors were considered during the experiments. The first analysed MB-MBR system was characterized by the use of Linpor® carriers (MB-MBRI), the other one by AnoxKaldnes™K1 carriers (MB-MBRII); in both systems an ultrafiltration membrane was used. The results showed a decrease of biological removal efficiencies for both systems mainly due to the total petroleum hydrocarbons (TPHs) playing an inhibitory role in the biomass growth; this was confirmed by negligible efficiencies in the removal of the TPHs. The analysis of the extracellular polymeric substances (EPSs) has highlighted a reduction of bound EPSs and a simultaneous increase of the protein fraction of the soluble microbial products (SMPs) likely due to the cellular lysis, as response to the increase of salinity and hydrocarbons concentration. No biofilm formation has occurred in MB-MBRII system while the MB-MBRI system showed an opposite behaviour. This fact has affected the fouling deposition on the membrane surface, indeed a biofilm detachment was observed in the MB-MBRI system which conditioned the irreversible cake deposition (showing an increase of 50% in the total resistance to filtration). On the other hand, the pore blocking was more evident in the MB-MBRII system (up to 61% of total resistance to filtration), likely due to the occlusion of the membrane’s porosity by the SMPs released into the mixed liquor through the cellular lysis.