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Aerobic granulation in sequencing batch reactors is widely reported in literature and in particular in SBAR (Sequencing batch airlift reactor) configuration, due to the high localised hydrodynamic shear forces that occur in this type of configuration. The aim of this work was to observe the phenomenon of the aerobic granulation and to confirm the excellent removal efficiencies that can be achieved with this technology. In order to do that, a laboratory-scale plant, inoculated with activated sludge collected from a conventional WWTP, was operated for 64 days: 42 days as a SBAR and 22 days as a SBBC (sequencing batch bubble column). The performances of the pilot plant showed excellent organics removal. COD and BOD removal efficiencies were respectively, 93 and 94%; on the contrary, N-removal efficiency was extremely low (5%-45%). The granules dimensions increased during the whole experimentation; change of reactor configuration contributed to further improve this aspect. The experimental work confirmed the essential role of hydraulic settling time in the formation of aerobic granules and in the sludge settleability and the need to find an optimum between granule size and oxygen supply to achieve good N-removal efficiency. [ABSTRACT FROM AUTHOR]

The growing increment of the urbanization and, on the other hand, the even more strict effluent limits imposed by the Water Framework Directive for the receiving water body quality state have led to the need for upgrading several existing WWTP. With this respect HMBBR systems are an innovative solution since they allow to upgrade existing high loaded WWTP without building new tanks. However, some uncertainties in their design, maintenance as well as performance have to be addressed due to their recent acquisition compared with well consolidated technologies such as activated sludge systems. In this light, a data gathering campaign on a HMBBR pilot plant has been performed. The aim was to detect the performance of such new technology as well as to survey the influencing effect of the carrier media filling ratio. Indeed, there may be problem of competitiveness between attached and suspended biomass that jointly operate in the same system for carbon and nitrogen removal. Such competitiveness may lead to a worsening of the system efficiency. The results are interesting and the gathered data in the experimental period show a slight difference in terms of performance behaviour, between the two systems (35 and 66%). Such result leads to address the filling ratio choice towards the 35%. [ABSTRACT FROM AUTHOR]

A semi-empirical mechanistic model able to simulate the dynamics of a stabilization reservoir was developed incorporating both settling of particulate components and chemical/biological processes. Several factors affecting the reservoir effluent quality were taken into account: hydraulics and hydrology, solar radiation, atmospheric reaeration, algae, zooplankton, organic matter, pathogen bacteria, and sediment-water interaction. The model quantifies the specific influence of each factor on effluent quality, evaluating the correlation between the different considered factors. State variables included in the model were: algae, dissolved oxygen, organic matter, zooplankton and indicator bacteria. The model was transferred into a computational code in order to provide a useful and versatile tool for water resource planning management issues. The model was verified by comparing simulated results with full-scale data collected from a small reservoir (Sicily, IT) filled with partially treated wastewater. The reservoir has a volume of 11,000m³, a maximum depth of 6.3m and a mean depth of about 5m. The monitoring period lasted four months during which the reservoir operated in different hydraulics conditions: as a standard batch reactor and as a continuous flow reactor. The model was able to reproduce the behaviour of the principal simulated parameters thus representing a potential tool for the management and performance optimization of these peculiar storage/treatment systems. [ABSTRACT FROM AUTHOR]

The present study has aimed to quantify the role of pore blocking and cake layer in a laboratory scale hollow fibre membrane module in submerged configuration. The membrane reactor (MBR) was fed with raw wastewater, only screened with a 2-mm sieve, collected from the Palermo WWTP. The MBR was characterised by an operating volume of 190 L and equipped with an aeration system located on the bottom of the reactor. The MBR operated for 65 days. The permeate was extracted by imposing a constant flux through the membrane (21 Lh-1m-2). The results confirm the importance of pore blocking control during start-up. In particular, it provides a rapid irreversible fouling that takes place at the beginning of the filtration process, before the deposition mechanism. Therefore, low suspended solids concentration in the initial phase causes a fast irreversible fouling. This circumstance creates the need for more frequent chemical cleaning after start-up without inoculum. Finally, the results underline that the cake has a mainly reversible feature. [ABSTRACT FROM AUTHOR]

In recent years there has been an increasing interest in the development of hybrid biofilm reactors, especially in the upgrading of existing WWFP that are no longer able to respect concentration limits. In fact, today's challenge is the achievement of a good aquatic state for the receiving water bodies according to the Water Framework Directive requirements, which indeed limit even more the continuous emissions, i.e. coming from WWTP. This paper presents the setting up of a mathematical model for the simulation of a hybrid MBBR system; the model calibration/validation has been carried out considering a field gathering campaign on an experimental pilot plant. The main goal is to gain insight about MBBR processes attempting to overcome main shortcomings in particular referring to the modelling aspects. The model is made up of two connected sub-models for the simulation of the suspended and attached biomass. The model is mainly based on the concepts of the activated sludge model No. 1 (ASM1) for the description of the biokinetic process both for the suspended and for the attached biomass. The results show a good agreement between predicted and observed values both for the attached and for the suspended biomass moreover they are encouraging for further researches. [ABSTRACT FROM AUTHOR]

• Biological and photocatalysis treatments in-series enabled high TOC removal (ca. 95%). • High photocatalysis performance was achieved because of the MBR pre-treatment. • The addition of K 2 S 2 O 8 reduced the necessity of cumulative impinging energy (60 E). • Membrane fouling mechanisms were the "cake layer deposition" and the "pore blocking". This study investigated the treatment of a shipboard slop containing commercial gasoline in a pilot plant scale consisting of a membrane biological reactor (MBR) and photocatalytic reactor (PCR) acting in series. The MBR contributed for approximately 70% to the overall slop purification. More precisely, the biological process was able to remove approximately 40%, on average, of the organic pollution in the slop. Nevertheless, the membrane was capable to retain a large amount of organic molecules within the system, amounting for a further 30% of the influent total organic content removal. However, this affected the membrane fouling, thus resulting in the increase of the pore blocking mechanism that accounted for approximately 20% to the total resistance to filtration (2.85∙1013 m−1), even if a significant restoration of the original membrane permeability was obtained after chemical cleanings. On the other hand, the biological treatment produced a clear solution for the photocatalytic system, thereby optimizing the light penetration and generation of highly oxidizing active oxygen species that enabled the degradation of bio-recalcitrant compounds. Indeed, low total organic carbon (TOC) values (<10 mg L−1) were achieved in the output of the photocatalytic reactor by means of only 60 Einstein (E) of cumulative impinging energy after the addition of K 2 S 2 O 8. Overall, coupling the two processes enabled very high TOC removal (ca. 95%). [ABSTRACT FROM AUTHOR]

This study investigated the treatment of a shipboard slop containing commercial gasoline in a pilot plant scale consisting of a membrane biological reactor (MBR) and photocatalytic reactor (PCR) acting in series. The MBR contributed for approximately 70% to the overall slop purification. More precisely, the biological process was able to remove approximately 40%, on average, of the organic pollution in the slop. Nevertheless, the membrane was capable to retain a large amount of organic molecules within the system, amounting for a further 30% of the influent total organic content removal. However, this affected the membrane fouling, thus resulting in the increase of the pore blocking mechanism that accounted for approximately 20% to the total resistance to filtration (2.85·1013 m-1), even if a significant restoration of the original membrane permeability was obtained after chemical cleanings. On the other hand, the biological treatment produced a clear solution for the photocatalytic system, thereby optimizing the light penetration and generation of highly oxidizing active oxygen species that enabled the degradation of bio-recalcitrant compounds. Indeed, low total organic carbon (TOC) values (<10m gL-1) were achieved in the output of the photocatalytic reactor by means of only 60 Einstein (E) of cumulative impinging energy after the addition of K2S2O8. Overall, coupling the two processes enabled very high TOC removal (ca. 95%). [ABSTRACT FROM AUTHOR]

A membrane bioreactor (MBR) pilot plant was operated in two subsequent experimental periods (namely, Periods I and II) with different start-up and sludge withdrawal strategies to study its peculiar biokinetic behavior by using respirometric techniques. Two extreme operational conditions were chosen to investigate the different biomass activity under dynamic or pseudostationary conditions during and after the start-up phases. Particularly, the MBR pilot plant was operated with the same volumetric loading rate (VLR) and permeate flux but differently managed during the start-up phase. In Period I, the MBR pilot plant was started up without sludge inoculum and operated without sludge withdrawals; on the contrary, in Period II the MBR pilot plant was started up with sludge inoculum and operated with regular sludge withdrawals. The obtained results highlighted that the different start-up strategies significantly affected the value of the yield coefficient, the storage phenomena, the decay coefficient, and the maximum respiration rates of heterotrophic species. More specifically, both experimental periods underlined interesting aspects related to the bacterial behavior under significant stress conditions occurring during a non-steady-state (start-up) phase. [ABSTRACT FROM AUTHOR]

A granular continuous-flow membrane bioreactor with a novel hydrodynamic configuration was developed to evaluate the stability of aerobic granular sludge (AGS). Under continuous-flow operation (Period I), AGS rapidly lost their structural integrity resulting in loose and fluffy microbial aggregates in which filamentous bacteria were dominant. The intermittent feeding (Period II) allowed obtaining the succession of feast and famine conditions that favored the increase in AGS stability. Although no further breakage occurred, the formation of new granules was very limited, owing to the absence of the hydraulic selection pressure. These results noted the necessity to ensure, on the one hand the succession of feast/famine conditions, and on the other, the hydraulic selection pressure that allows flocculent sludge washout. This preliminary study shows that the proposed configuration could meet the first aspect; in contrast, biomass selection needs to be improved. [ABSTRACT FROM AUTHOR]

Objectives: Since the new millennium, the number of e-health users has significantly increased. Among these, a particular category of people who are interested by this phenomenon is the one of pregnant women. The aim of the present study is to assess the sociodemographic and geographic differences existing in a sample of Italian pregnant women who search for information on the web. Study design: Multicenter cross-sectional survey. Methods: The present study has been conducted from November 2011 to September 2012, in seven Italian cities, located in the North, in the Centre and in the South of Italy. Data were collected through an anonymous questionnaire, administered in waiting rooms of outpatient departments by trained medical doctors. Data were analysed through multivariate logistic regression models. Results: Overall, 1347 responders were interviewed. Eighty-six percent of them declared to surf the internet to retrieve pregnancy-related information. The most searched topics were fetal development (51.3%), healthy lifestyle during pregnancy (48.7%), physiology of pregnancy (39.8%), generic and specific tips/advices during pregnancy (37.2%) and lactation (36.8%). Statistically significant differences (P < 0.05) according to geographic origin, age and educational level were found with regard to the most frequently searched information on the Web, the reasons that pushed pregnant women to practice e-health, and the possibility to change lifestyles after e-health. [ABSTRACT FROM AUTHOR]

The effect of intermittent aeration (IA) on a MBR system was investigated. The study was aimed at analyzing different working conditions and the influence of different IA cycles on the biological performance of the MBR pilot plant, in terms of organic carbon and ammonium removal as well as extracellular polymeric substances (EPSs) production. The membrane modules were placed in a separate compartment, continuously aerated. This configuration allowed to disconnect from the filtration stage the biological phenomena occurring into the IA bioreactor. The observed results highlighted good efficiencies, in terms of organic carbon and ammonium removal. It was noticed a significant soluble microbial products (SMPs) release, likely related to the higher metabolic stress that anoxic conditions exerted on the biomass. However, the proposed configuration, with the membranes in a separate compartment, allowed to reduce the EPSs in the membrane tank even during the non-aerated phase, thus lowering fouling development. [ABSTRACT FROM AUTHOR]