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The present study reports the results on the comparison between the oxygen transfer efficiency in a conventional activated sludge (CAS) and membrane bioreactor (MBR) system. The oxygen transfer was evaluated by means of the oxygen transfer coefficient (kLa)20 and α-factor calculation, under different operating conditions and with different activated sludge features, including total suspended solids (TSS) concentration, extracellular polymeric substances (EPS) content and composition, sludge viscosity and size of the flocs. The (kLa)20 and α-factor showed an exponential decreasing trends with TSS in the CAS and MBR, even if it was noted that the (kLa)20 dependence on TSS was stronger in the CAS than the MBR. Under the typical operating TSS concentration for CAS (3 gTSS L-1) and MBR (8 gTSS L-1), the obtained results indicated that oxygen transfer coefficient was lower in the MBR (3.6 h-1 vs 20 h-1). Nevertheless, it was noted that the (kLa)20 in the CAS become comparable to that in MBR when the TSS concentration in the CAS was higher than 5 gTSS L-1, which is typical of plants operating under extended aeration. Within a range of TSS between 4 gTSS L-1 and 6 gTSS L-1 the (kLa)20 value resulted significantly higher in the MBR, thereby suggesting that under similar operating conditions the features of the activated sludge flocs in the MBR were more favorable to oxygen diffusion. Operating under high C/N, as a result of nutrients unbalance, the (kLa)20 increased in both the CAS and MBR because of the sludge deflocculation and, overall, a weaker dependence of (kLa)20 with TSS in both the systems was noted. The obtained results indicated that the most important investigated parameters on the oxygen transfer efficiency were in order: the TSS concentration, flocs size, sludge viscosity, PN/PS and EPS content. More precisely, the TSS, the EPS, the viscosity and the flocs size had a negative influence, meaning that an increase in these parameter led to a decrease of the (kLa)20, whereas the only parameter having a positive influence was the PN/PS. The TSS concentration had a greater influence on (kLa)20 in the CAS than the MBR, as well as the EPS. In contrast, the activated sludge viscosity, the flocs size and the PN/PS had a greater influence in the MBR. Based on the influence of the main biomass features affecting the (kLa)20 and considering the typical operating conditions in both systems, those of the MBR appeared to be more favorable to oxygen transfer efficiency compared to CAS.

The aim of this work was to investigate the effects of moderate and drastic long-termincrease of salinity.Particularly, the study was aimed at assessing the shock effecton nitritationand denitritation kineticsof halophilic biomass inboth forms:flocculent activated sludge and granular sludge.

The paper reports the main results from an experimental gathering campaign carried out on a bench scale plant for the evaluation of hydrocarbon effect on the system performance. In particular, a membrane bioreactor (MBR) under submerged configuration was analysed. The MBR plant was fed with synthetic wastewater containing hydrocarbons. Organic carbon, hydrocarbons and ammonium removal, kinetic constants, extracellular polymeric substances (EPSs) production and membranes fouling rates have been assessed. The observed results highlighted good system performance in terms of both COD removal and nitrification, thus showing a sort of biomass adaptation to hydrocarbon. Such a result has been also confirmed by the biomass respirometric tests. Moreover, membrane fouling analysis showed an increase of the total resistance in the last period of the experiments. Such a result was most likely due to the hydrocarbon which caused an irreversible fouling due to oil deposition onto the membrane surface.

During the last years many advances have matured in wastewater treatment both in terms of processes and mathematical modelling approaches. For a new generation of new scientists and engineers entering/working in the wastewater treatment field, the quantity, complexity and diversity of these new developments can be overwhelming. This Advanced Course on Innovative wastewater treatment processes and mathematical modelling will provide a comprehensive overview and a discussion platform for recent advances and trends currently under development in the context of wastewater treatment. This course is aimed at professionals (Master, PhD or equivalent experience) in wastewater treatment and mathematical modelling with a basic working knowledge of the two other disciplines. The course is primarily aimed at those already employed in industry who wish to up- date their theoretical knowledge and practical insight in this field.

The paper reports the main results of an experimental campaign carried out on two bench scale pilot plants for treatment of synthetic shipboard slops. In particular, two membrane bioreactors (MBRs) with submerged configuration were analyzed. One MBR pilot plant (namely, Line A) was fed with synthetic shipboard slop and was subjected to a gradual increase of salinity. Conversely, the second MBR pilot plant (namely, Line B) was fed with the same synthetic shipboard slop but without salt addition, therefore operating as a “control” unit. Organic carbon, hydrocarbons and ammonium removal, kinetic constants, extracellular polymeric substances (EPSs) production and membranes fouling rates have been assessed. The observed results highlighted a stress effect exerted by salinity on the biological performances, with lower removal efficiencies in the Line A compared to Line B. Significant releases of soluble EPS in Line A promoted an increase of the resistance related to particle deposition into membrane pores (pore fouling tendency), likely due to a worsening of the mixed liquor features. Such a condition enhanced the reduction of the “pre-filter” effect of the cake layer.

COD AND TPH ANALYSIS IN SLOPS EXPERIMENTAL TREATMENT PLANTS: ANALYTICAL PROBLEMS. In the last years, the persistence and accumulation of xenobiotic compounds in the environment created many disposal problems of oily wastewater generated by ships, mainly in engine-rooms (bilge waters) and by cleaning of tanker (slops). The high salinity levels (up to 25.000 mgL-1) and the pollutants concentration, both limit the chances of discharge into the sewer systems and address the disposal of these wastewaters to the sea. For these reasons it is necessary to treat such wastewater efficiently before discharging [1]. As a part of a broader project concerning slops treatments, this work addresses issues related to the analytical methods of the COD and TPH parameters, chosen under the provisions of Italian Legislative Decree 152/06, that implements the European directives on environmental protection. In the COD analysis the greatest difficulty was the high salinity levels corresponding to high chlorides levels. Chlorides cause a positive interference in the measurement, and this interference during the analysis of COD was investigated at various concentrations of mercury in order to try to minimize the use of this reagent that causes many problems of safety and disposal, and at different times reaction [2][3][4]. The major problems in TPH analysis concerned correct setup of the gas chromatographic separation, high variability in sample composition and the high capacity of the sample to form emulsions during the liquid-liquid extraction procedure. This paper reports the results of the analysis of COD and TPH and the problems related to the development of a suitable analytical method for the analysis of these specimens. This study is part of STITAM European project, created with the aim to develop innovative technologies for the treatment of liquid wastes of navigation, in order to better safeguard marine environment. [1] G. Mancini, S. Cappello, M.M. Yakimov, A. Polizzi, M. Torregrossa, Chemical Engineering Transactions 27 (2012) 37-42. [2] I. Vyrides, D.C. Stuckey, Bioresource Technology 100 (2009) 979–982 [3] Alexandra M.E. Viana da Silva, Ricardo J.N. Bettencourt da Silva , M. Filomena G.F.C. Camoes, Analytica Chimica Acta 699 (2011) 161– 169 [4] D.D.C. Freire, G.L. Sant’anna jr, Environmental Technology 19 (1998) 1243- 1247

The paper focused on the evolution of extracellular polymeric substances (EPSs) content during the granulation process in two Granular Sequencing Batch Airlift Reactors (GSBAR) (3,5 L) fed with synthetic and industrial wastewater. Results showed that EPSs, in particular proteins (PN) were mainly produced during the feast phase because of high substrate availability, especially under conditions of metabolic stress. Than EPSs content reduced during the famine period. More in detail, during the granulation process, a greater polysaccharides (PS) consumption occurred in both reactors, while PN content reduced significantly only in R2. As a result PN/PS ratio increased significantly during granules formation, confirming the key role of proteins on granules formation. R2 granules exhibited a greater amount of PN on average, and this resulted in a more rapid granulation. However, due to the several consumption of PN during the famine period, R2 granules resulted weaker an less dense than R1 ones, hence more susceptible to breakdown. When EPSs consumption during the famine phase reduced, granules reached their maturation.

This study was focused on the microbial community characterization during operation of a Membrane Bioreactor System, used for the treatment of saline oily wastes, originated from marine transportation. A collection of forty-two (42) strains was obtained during microbiological screening and the bacterial diversity analyzed by amplification and 16S rRNA sequencing. Taxonomic analysis has shown a high level of identity with recognized sequences for a total of seven (7) distinct bacterial genera (Alcanivorax, Erythrobacter, Marinobacter, Microbacterium, Muricauda, Rhodococcus and Rheinheimera). The biotechnological potential of all isolates was identified by the estimate of two key factors, such as the production of biosurfactants (drop collapse test, oil spreading and E24 test) and the cellular adhesion percentage of hydrophobicity). These tests have been proposed for their ease of use and reliability in relation to the bacterial culture's ability to reduce the surface tension. The production of biosurfactants, forms part of several adaptations made by the microorganisms to metabolize hydrocarbons and represents a physiological response to specific environmental needs. Fourteen (14) biosurfactant producing bacteria were identified among all isolates and were further selected for growth on crude oil (optical density, OD600nm) and hydrocarbons degradation test(GC-FID analysis). Data obtained from this study confirmed the high potential of bacteria related to genera Alcanivorax (isolates MBR-B11 and MBR-G10), Rhodococcus (isolates MBR-F04 and MBR-G05), Rheinheimera (isolates MBR-H02 and MBR-H05), and Muricauda (isolate MBR-G04) and their possible application in petrolchemical waste water environmental problems. Our overall results suggest that the obtained bacterial isolates may constitute potential candidates for bioremediation and can be useful for biotechnological applications.

The paper presents the results of a field gathering campaign carried out on two different pilot scale membrane bioreactor (MBR) systems, treating synthetic wastewater subject to a gradual increase of salinity. One was a conventional MBR system, while the other was a moving bed biofilm membrane bioreactor (MB-MBR), which combines suspended biomass and biofilm. Indeed, the presence of suspended carriers inside the bioreactor seems to give benefits due to the collisions between the circulating media and the membrane. The aim of the study was the comparison of two configurations in terms of biomass activity characterization and performance (pollutants removal and hydraulic behaviour). The results highlighted a significant biomass activity for both heterotrophic and autotrophic populations. Such behaviour was emphasized in MB-MBR system, likely due to the presence of biofilm attached on suspended sponge carriers, which is characterized by high retention times, thus improving through the “seeding” effect the nitrification ability of the whole system.