Development of a biofilm-MBR for shipboard wastewater treatment: The effect of process configuration

Performance of membrane bioreactor (MBR) systems for the treatment of shipboard slops: Assessment of hydrocarbon biodegradation and biomass activity under salinity variation

“…3 in terms of TS fraction, the biomass developed on the sponge carriers accounted for 4.5 g TS L −1 even at the beginning of sub-phase I 2 . Subsequently, the biofilm showed an increasing trend with concentrations equal to 8.5 g TS L −1 in sub-phase I 3 and 9-10 g TS L −1 in sub-phase I 5 . In Phase II, the biofilm concentration showed a slight decrease during sub-phases II 1 -II 3 , likely due to the stress effect exerted by the increasing percentage of slops fed to the plant.…”

“…5c. Indeed, although a decrease of nitrification efficiency was observed upon each salinity variation, especially in sub-phases I 4 and I 5 , throughout Phase I an overall increase in nitrification was observed, with an efficiency reaching 90% at the end of sub-phase I 5 . According to previous experiences [32], the gradual increase of salinity can aid to better sustain nitrification.…”

“…However, MBMBRs are relatively new, and a knowledge gap still exists, especially referring to the effects of salinity and recalcitrant organic substrates, with very few studies reported so far [38]. Furthermore, the treatment of shipboard slops with hybrid MBR systems has been investigated only in pilot scale studies with synthetic wastewater, while to the authors' knowledge, no studies with real shipboard slops are available [5,18]. Therefore, since the knowledge level is still in its infancy, further studies and research activities are needed.…”

“…This aspect is of particular concern when considering specific activities producing saline wastewater that might be characterised by highly recalcitrant, toxic and slowly biodegradable compounds, such as the fish canning, petroleum, petrochemical and tannery industries [1][2][3][4]. In this context, an important issue is represented by the treatment of wastewater produced during shipboard activities (bilge water or slops), which usually features high oily and saline concentrations [5]. It is worth noting that the direct discharge of wastewater from ships is prohibited by the International Maritime Organization (IMO) regulations [6].…”

“…Although physicochemical methods have been successfully applied in the past [8,9], they impose several issues with regards to chemical consumption, high energy requirements and secondary pollution. Conversely, the use of biological treatments is becoming increasingly popular in the field of saline wastewater characterised by high organic content and petroleum hydrocarbons [5,[10][11][12][13][14][15], even if the presence of high concentrations of a separate oily phase usually requires proper pre-treatment [16]. In recent years, membrane bioreactors (MBRs) have been applied for saline wastewater treatment [17][18][19][20].…”