16 results on '"VIVIANI, Gaspare"'
Search Results
2. A mathematical model for a sequential batch membrane bioreactor pilot plant
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MANNINA, Giorgio, COSENZA, Alida, VIVIANI, Gaspare, Mannina, G., Cosenza, A., and Viviani, G.
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Settore ICAR/03 - Ingegneria Sanitaria-Ambientale ,Wastewater treatment ,membrane ,calibration ,uncertainty analysis ,measured data ,uncertainty analysi - Abstract
A mathematical model to quantify the nitrogen removal for a membrane bioreactor (MBR) has been presented in this study. The model has been applied to a pilot plant having a pre-denitrification MBR scheme. The pilot plant was cyclically filled with real saline wastewater according to the fill-draw-batch operation. The model was calibrated by adopting a specific protocol based on extensive field dataset. The Standardized Regression Coefficient (SRC) method was adopted to select the most influential model factors to be calibrated. Results related to the SRC method have shown that model factors of the efficiency of backwashing and the biological factors affecting the soluble microbial products (utilization-associated products) (namely, fUAP and KH,UAP) strongly affects the membrane resistance. In terms of model calibration excellent results in terms of model efficiency were found for the total membrane resistance model output (efficiency equal to 0.79). Regarding the biological model outputs acceptable were found in the case an high number of measured data was available. In terms of uncertainty, it was found that for the great part of the analyzed model outputs the measured data lay inside the uncertainty bands.
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- 2016
3. Analysis of Biomass Characteristics in MBR and MB-MBR Systems Fed with Synthetic Wastewater: Influence of a Gradual Salinity Increase
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Di Bella, G, DI TRAPANI, Daniele, Freni, G, TORREGROSSA, Michele, VIVIANI, Gaspare, Di Bella, G, Di Trapani, D, Freni, G, Torregrossa, M, and Viviani, G
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lcsh:Computer engineering. Computer hardware ,Settore ICAR/03 - Ingegneria Sanitaria-Ambientale ,Biofilm ,Bioreactor ,Circulating media ,lcsh:TP155-156 ,lcsh:TK7885-7895 ,Wastewater treatment ,Retention time ,Moving bed ,Membrane bioreactor ,Pilot-scale membrane ,Biomass activity ,lcsh:Chemical engineering ,Pollutants removal ,Hydraulic behaviour ,Synthetic waste water - Abstract
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.
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- 2014
4. Treatment of Oily Wastewater with Membrane Bioreactor Systems.
- Author
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Capodici, Marco, Cosenza, Alida, Di Trapani, Daniele, Mannina, Giorgio, Torregrossa, Michele, and Viviani, Gaspare
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MEMBRANE reactors ,WASTEWATER treatment ,DIESEL fuels ,FOULING ,HYDROCARBONS - Abstract
The aim of the present work was to investigate the behavior of a membrane bioreactor (MBR) system for the treatment of oily wastewater. A bench scale MBR was fed with synthetic wastewater containing diesel fuel. Organic carbon, hydrocarbon and ammonium removal, kinetic constants, extracellular polymeric substances production, and membrane fouling rates were monitored. The MBR plant was operated for more than 200 days, and the results highlighted good carbon removal and nitrification, suggesting a sort of biomass adaptation to hydrocarbons. Membrane fouling analysis showed an increase in total resistance, likely due to hydrocarbons, which caused an irreversible fouling (pore blocking) mainly due to oil deposition. [ABSTRACT FROM AUTHOR]
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- 2017
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5. Wastewater Reuse Effects on Soil Hydraulic Conductivity.
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Viviani, Gaspare and Iovino, Massimo
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SOIL permeability , *INDUSTRIAL wastes , *WASTEWATER treatment , *WATER reuse , *SOIL infiltration , *FRESH water - Abstract
The wastewater total suspended solids (TSS) concentration effects on the saturated hydraulic conductivity, Ks, of a clay and a loam soil were investigated on laboratory repacked soil cores by a constant head permeameter. Both municipal wastewater (MW) and artificial wastewater (AW) with different TSS concentrations were used, with the aim to evaluate, by comparison, the effects of biological activity. The development of a surface sealed layer was investigated in loam soil columns supplied with AW and equipped with water manometers at different depths to detect the hydraulic head gradient changes. In the loam soil, Ks reduced to about 80% of the initial value after infiltration of 175 mm of MW with TSS=57–68 mg L-1. Reductions in Ks were more remarkable in the clay soil. An empirical relationship was proposed to predict the relative hydraulic conductivity, Kr, i.e., the ratio between actual and initial hydraulic conductivity versus the cumulative density loading of TSS. Hydraulic head gradients in the top layer (0–20 mm) of the soil columns increased during application of AW, as a consequence of the formation of a sealed layer, denoting that the surface pore sealing was the main mechanism responsible for the observed Ks reductions. Laboratory data were gathered in a numerical simulation code specifically created to assess the consequences of Ks reduction on water movement through the soil profile. Simulation of both ponded and sprinkler irrigation with MW resulted in reduced infiltration and increased surface ponding condition compared to the application of fresh water (FW). [ABSTRACT FROM AUTHOR]
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- 2004
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6. Membrane Bioreactors for wastewater reuse: Respirometric assessment of biomass activity during a two year survey.
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Di Trapani, Daniele, Mannina, Giorgio, and Viviani, Gaspare
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WASTEWATER treatment , *MEMBRANE reactors , *BIOMASS , *WATER shortages , *ACTIVATED sludge process - Abstract
Abstract Stricter effluent limits, water shortage conditions, land availability requires today even more the needs of advanced wastewater treatments. Attractive solutions come from membrane bioreactors (MBR), Integrated Fixed Film Activated Sludge (IFAS) or combinations (i.e., IFAS-MBRs). One crucial aspect for the applicability of this overall new technology, compared to the conventional activated sludge systems, is the lack of knowledge for design and manage (e.g., kinetic constants, optimal operative conditions etc.). In view of the above frame, the aim of the present study was to assess the kinetic and stoichiometric parameters of bacterial species in MBRs by means of respirometric techniques. Plant configurations, operational conditions and wastewater features (domestic/industrial) were analysed. Four different MBR plants were investigated: i) sequencing batch MBR subjected to a gradual salinity increase; ii) pre-denitrification MBR treating saline wastewater contaminated by hydrocarbons; iii) University of Cape Town (UCT) MBR treating domestic wastewater subjected to a carbon-to-nitrogen (C/N) ratio variation; iiii) UCT- IFAS -MBR treating domestic wastewater. Results show a significant influence on biomass respiratory activity from both plant configurations and operational conditions. The salinity increase severely affected the activity of autotrophic species, while heterotrophic community was mainly influenced by the C/N variation. Moreover, it was observed a specialization in the IFAS-MBR configuration, with the suspended biomass more affine to organic matter, whilst biofilm in the nitrification process. The respirometric analysis confirmed to be an effective tool for the evaluation of the biomass kinetic and stoichiometric parameters. The results of this study can be useful for the application of mathematical models in the design phase and for the monitoring of biomass viability during plant operations. Graphical abstract Image 1 Highlights • The study aim was to provide new insights on biokinetic behaviour of MBRs. • Respirometry was used to assess the kinetic and stoichiometric coefficients. • Heterotrophs highly suffered low C/N ratio with increased membrane fouling. • Salinity highly affected the autotrophic activity increasing the pore blocking. • It was observed a specialization of suspended and attached biomass in the IFAS-MBR. [ABSTRACT FROM AUTHOR]
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- 2018
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7. Sensitivity and uncertainty analysis of an integrated ASM2d MBR model for wastewater treatment.
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Mannina, Giorgio, Cosenza, Alida, Viviani, Gaspare, and Ekama, George A.
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WASTEWATER treatment , *MEMBRANE reactors , *BIOREACTORS , *REGRESSION analysis , *SENSITIVITY analysis , *MONTE Carlo method - Abstract
An integrated membrane bioreactor (MBR) model was previously proposed and tested. The model provides a comprehensive and detailed description of the nitrogen biological removal processes with respect to up-to-date literature. This paper presents a sensitivity and uncertainty analysis aimed at identifying the key factors affecting the variability of the model predictions. The Standardized Regression Coefficients (SRC) method was adopted for the sensitivity analysis. The uncertainty analysis was employed by running Monte Carlo simulations by varying only the value of the key factors affecting the model outputs. The sensitivity analysis combined with the uncertainty analysis applied here enabled to gain useful insights about the robustness of the model. By means of the SRC method 45 model factors (of 122) were selected as important. The results obtained here allowed to investigate the advantage of a detailed description of the nitrogen transformation bioprocesses (nitrification/denitrification) in terms of model accuracy and uncertainty bandwidth. The model allows to simulate the intermediate product during nitrification/denitrification, thus providing the possibility to control the nitrogen compounds that favour the formation of nitrous oxide. [ABSTRACT FROM AUTHOR]
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- 2018
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8. PHA and EPS production from industrial wastewater by conventional activated sludge, membrane bioreactor and aerobic granular sludge technologies: A comprehensive comparison.
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Traina, Francesco, Capodici, Marco, Torregrossa, Michele, Viviani, Gaspare, and Corsino, Santo Fabio
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INDUSTRIAL wastes , *SEWAGE , *WASTEWATER treatment , *ACTIVATED sludge process , *EFFLUENT quality , *SLUDGE management , *SEWAGE disposal plants - Abstract
The present study has focused on the mainstream integration of polyhydroxyalkanoate (PHA) production with industrial wastewater treatment by exploiting three different technologies all operating in sequencing batch reactors (SBR): conventional activated sludge (AS-SBR), membrane bioreactor (AS-MBR) and aerobic granular sludge (AGS). A full aerobic feast/famine strategy was adopted to obtain enrichment of biomass with PHA-storing bacteria. All the systems were operated at different organic loading (OLR) rate equal to 1-2-3 kgCOD/m3∙d in three respective experimental periods. The AS-MBR showed the better and stable carbon removal performance, whereas the effluent quality of the AS-SBR and AGS deteriorated at high OLR. Biomass enrichment with PHA-storing bacteria was successfully obtained in all the systems. The AS-MBR improved the PHA productivity with increasing OLR (max 35% w/w), whereas the AS-SBR reduced the PHA content (max 20% w/w) above an OLR threshold of 2 kgCOD/m3∙d. In contrast, in the AGS the increase of OLR resulted in a significant decrease in PHA productivity (max 14% w/w) and a concomitant increase of extracellular polymers (EPS) production (max 75% w/w). Results demonstrated that organic carbon was mainly driven towards the intracellular storage pathway in the AS-SBR (max yield 51%) and MBR (max yield 61%), whereas additional stressors in AGS (e.g., hydraulic selection pressure, shear forces) induced bacteria to channel the COD into extracellular storage compounds (max yield 50%) necessary to maintain the granule's structure. The results of the present study indicated that full-aerobic feast/famine strategy was more suitable for flocculent sludge-based technologies, although biofilm-like systems could open new scenarios for other biopolymers recovery (e.g., EPS). Moreover, the AS-MBR resulted the most suitable technology for the integration of PHA production in a mainstream industrial wastewater treatment plant, considering the greater process stability and the potential reclamation of the treated wastewater. [Display omitted] • A mainstream process for PHA production was integrated with wastewater treatment. • A comparison between AS, AGS and MBR as the enrichment/treatment stage was assessed. • MBR enabled the highest PHA production potential and effluent water eligible for reuse. • Biomass enrichment under full aerobic in AGS promoted extracellular storage pathways. • Integration of PHA production in the mainstream of a WWTP resulted feasible using MBR. [ABSTRACT FROM AUTHOR]
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- 2024
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9. An integrated model for biological and physical process simulation in membrane bioreactors (MBRs)
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Mannina, Giorgio, Di Bella, Gaetano, and Viviani, Gaspare
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MEMBRANE reactors , *SIMULATION methods & models , *MATHEMATICAL models , *WASTEWATER treatment , *FOULING , *AERATION tanks , *MONTE Carlo method - Abstract
Abstract: Mathematical modelling of membrane bioreactors (MBRs) for wastewater treatment has targeted either the biological processes (treatment quality target) as well as various aspects of system management. However, the high number of interactions among the involved physical–chemical processes, hampers a straightforward mathematical modelling. This circumstance is much more emphasized for submerged MBR systems where the membrane is immersed in an aeration tank. One of the main crucial points that prevents a comprehensive understanding is the interpretation of the fouling phenomenon and its connections with the biological processes. An overall mathematical model for MBR has not been completely established yet. Indeed, existing MBR models are generally focused only on some of the involved processes (e.g. biological, physical, chemical, etc.) to analyze limited MBR aspects. However, a comprehensive integrated mathematical approach aimed at an in-depth analysis is warmly recommended in order to optimize the whole MBR system. Seeking the development of the area, the paper presents an integrated MBR model that simulates and takes into account both biological and physical processes. An innovative calibration protocol was applied to evaluate the model parameter values as well. This protocol is based on a preliminary global sensitivity analysis to reduce the number of model parameters to be calibrated to the most influential ones. The calibration protocol consists of a novel step-wise Monte Carlo based calibration of the subset of influential parameters. The key point of the step-wise procedure is that calibration is carried out for sub-groups of variables instead of solving a complex multi-objective function. The model results compare fairly well with the experimental results of a MBR pilot plant. [Copyright &y& Elsevier]
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- 2011
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10. An integrated model for physical-biological wastewater organic removal in a submerged membrane bioreactor: Model development and parameter estimation
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Di Bella, Gaetano, Mannina, Giorgio, and Viviani, Gaspare
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WASTEWATER treatment , *BIOREACTORS , *MATHEMATICAL models , *WASTE management - Abstract
Abstract: The paper presents the setting up of a mathematical model for membrane bioreactor able to simulate physical-biological wastewater organic removal. The model is basically divided into two sub-models: the first sub-model is basically devoted for the simulation of the biological features and the second one for the physical processes. In particular regarding the biological aspects, the ASM concept has been employed. On the other hand, the physical processes have been modelled considering the deep-bed theory taking into account not only the effect of the physical membrane filtration but also the cake layer effect. This latter operates as a biological membrane leading to a further reduction of the effluent COD. The model was applied to a SMBR pilot plant characterized by hollow fibre membrane module in submerged configuration. The SMBR was fed by raw wastewater collected from the Palermo (IT) WWTP and it was in operation for a total period of 130 days. During the whole experimentation the TSS was maintained meanly constant with periodic sludge withdrawal, in order to analyse the role of cake layer on organic removal. The model results are interesting and confirm the importance of cake deposition in the filtration process. The developed model can be employed as a useful tool in optimizing operation conditions as well as design issues for SMBR systems. [Copyright &y& Elsevier]
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- 2008
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11. Combined recovery of polyhydroxyalkanoates and reclaimed water in the mainstream of a WWTP for agro-food industrial wastewater valorisation by membrane bioreactor technology.
- Author
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Traina, Francesco, Corsino, Santo Fabio, Capodici, Marco, Licitra, Enrico, Di Bella, Gaetano, Torregrossa, Michele, and Viviani, Gaspare
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INDUSTRIAL wastes , *SEWAGE , *POLYHYDROXYALKANOATES , *WASTEWATER treatment , *CIRCULAR economy , *WATER reuse - Abstract
The present study investigated the combined production of reclaimed water for reuse purposes and polyhydroxyalkanoates (PHA) from an agro-food industrial wastewater. A pilot plant implementing a two-stage process for PHA production was studied. It consisted of a mainstream sequencing batch membrane bioreactor (SBMBR) in which selection of PHA-accumulating organisms and wastewater treatment were carried out in, and a side-stream fed-batch reactor (FBR) where the excess sludge from the SBMBR was used for PHA accumulation. The performance of the SBMBR was compared with that of a conventional sequencing batch reactor (SBR) treating the same wastewater under different food to microorganisms' ratios (F/M) ranging between 0.125 and 0.650 kgCOD kgTSS−3 d−1. The SBMBR enabled to obtain very high-quality effluent in compliance with the relevant national (Italy) and European regulations (Italian DM 185/03 and EU, 2020/741) in the field of wastewater reclamation, whereas the performances in the SBR collapsed at F/M higher than 0.50 kgCOD kgTSS−1d−1. A maximum intracellular storage of 45% (w/w) and a production yield of 0.63 gPHA L−1h−1 were achieved when the SBMBR system was operated with a F/M ratio close to 0.50 kgCOD kgTSS−1d−1. This resulted approximately 35% higher than those observed in the SBR, since the ultrafiltration membrane avoided the washout of dispersed and filamentous bacteria capable of storing PHA. Furthermore, while maximizing PHA productivity in conventional SBR systems led to process dysfunctions, in the SBMBR system it helped mitigate these issues by reducing membrane fouling behaviour. The results of this study supported the possibility to achieve combined recovery of reclaimed water and high-value added bioproducts using membrane technology, leading the way for agro-food industrial wastewater valorization in the frame of a circular economy model. [Display omitted] • A mainstream SBMBR was used for the combined recovery of treated water and PHA. • SBMBR effluent complied with reuse limits set by the current European regulations. • PHA performance (45% w/w and 0.63 gPHA L−1h−1) were higher in the SBMBR than the SBR. • Competitive reactions to PHA accumulation (EPS synthesis) were limited in the SBMBR. • PHA accumulation significantly reduced the membrane fouling tendency. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Aerobic granular sludge treating high strength citrus wastewater: Analysis of pH and organic loading rate effect on kinetics, performance and stability.
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Corsino, Santo Fabio, Di Trapani, Daniele, Torregrossa, Michele, and Viviani, Gaspare
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SLUDGE management , *WASTEWATER treatment , *HYDROLYSIS , *ENVIRONMENTAL management , *FILAMENTOUS bacteria - Abstract
In the present paper, the feasibility of citrus wastewater treatment with aerobic granular sludge sequencing batch reactors (AGSBR) was investigated. Two AGSBRs (named R1 and R2, respectively) were operated for 90 days under different organic loading rates (OLR) and pH in two experimental periods. The OLR ranged approximately between 3.0 kg TCOD m −3 d −1 and 7 kg TCOD m −3 d −1 during Period I, whereas between 7 kg TCOD m −3 d −1 and 15 kg TCOD m −3 d −1 during Period II. pH was maintained at 7.0 and 5.5 in R1 and R2, respectively. The results revealed that under high OLR and unbalanced feast/famine regime (Period I), the development of fast-growing microorganisms (fungi and filamentous bacteria) was favoured in both reactors, resulting in granular sludge instability. An extended famine phase and a proper balancing between feast and famine periods (Period II) were favourable for the development of bacteria with low growth rates (0.05 d −1 ) thus enhancing the granules stability. To the benefit of granular sludge stability and effluent quality, the length of the feast period should not exceed 25% of cycle length. Moreover, under OLR lower than 7 kg TCOD m −3 d −1 the removal efficiency of total chemical oxygen demand (TCOD) was approximately 90% in R1 and R2 and no side effects on the organic carbon removal performance related to the pH were observed. In contrast, at higher OLR a significant decrease in the removal efficiency (from 90% to less than 75%) was observed in R2. Results revealed also that under low pH, hydrolysis of proteins occurred and a decrease in the biological kinetic rates proportionally to the applied OLR was observed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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13. Shortcut nitrification-denitrification by means of autochthonous halophilic biomass in an SBR treating fish-canning wastewater.
- Author
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Capodici, Marco, Corsino, Santo Fabio, Torregrossa, Michele, and Viviani, Gaspare
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NITRIFICATION , *BIOMASS , *FISH canneries , *BIOCHEMICAL oxygen demand , *WASTEWATER treatment - Abstract
Autochthonous halophilic biomass was cultivated in a sequencing batch reactor (SBR) aimed at analyzing the potential use of autochthonous halophilic activated sludge in treating saline industrial wastewater. Despite the high salt concentration (30 g NaCl L −1 ), biological oxygen demand (BOD) and total suspended solids (TSS), removal efficiencies were higher than 90%. More than 95% of the nitrogen was removed via a shortcut nitrification-denitrification process. Both the autotrophic and heterotrophic biomass samples exhibited high biological activity. The use of autochthonous halophilic biomass led to high-quality effluent and helped to manage the issues related to nitrogen removal in saline wastewater treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurations.
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Corsino, Santo Fabio, Carabillò, Michele, Cosenza, Alida, De Marines, Federica, Di Trapani, Daniele, Traina, Francesco, Torregrossa, Michele, and Viviani, Gaspare
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EFFLUENT quality , *ANAEROBIC reactors , *BIOLOGICAL nutrient removal , *LYSIS , *WATER treatment plant residuals , *PLANT layout , *RF values (Chromatography) - Abstract
In the present research, insights about the mechanisms of excess sludge minimization occurring in an oxic-settling-anaerobic (OSA) were provided. The investigation involved two systems operating in parallel. In particular, a conventional activated sludge (CAS) system as control and a system implementing the OSA process both having a pre-denitrification scheme were considered. Five periods (P1–P5) were studied, during which several operating conditions and configurations were tested. Specifically, the hydraulic retention time (HRT) in the anaerobic reactor of the OSA system (P1 8 h, P2–P3 12 h, P4 8 h, P5 12 h) and the return sludge from the anaerobic to the anoxic (scheme A) (P1–P2) or aerobic (scheme B) mainstream reactors (P3–P5) were investigated. The results highlighted that the excess sludge production in the OSA was lower in all the configurations (12–41%). In more detail, the observed yield (Y obs) was reduced from 0.50-0.89 gTSS gCOD−1 (control) to 0.22 -0.34 gTSS gCOD−1 in the OSA process. The highest excess sludge reduction (40%) was achieved when the OSA was operated according to scheme B and HRT of 12 h in the anaerobic reactor (P3). Generally, scheme A enabled the establishment of cell lysis and extracellular polymeric substances (EPS) destructuration, leading to a worsening of process performances when high anaerobic HRT (>8 h) was imposed. In contrast, scheme B enabled the establishment of maintenance metabolism in addition to the uncoupling metabolism, while cell lysis and EPS destruction were minimized. This allowed obtaining higher sludge reduction yield without compromising the effluent quality. [Display omitted] • An OSA process with a novel plant layout enabled excess sludge reduction up to 40%. • Cell lysis and EPS destruction were enhanced by operating under prolonged anaerobiosis. • Cell lysis and EPS hydrolysis impaired effluent quality and sludge settling features. • Maintenance and uncoupling metabolism enabled higher sludge reduction (26–40%). • Nitrifiers were affected by prolonged starvation under not aerobic conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Biopolymer Recovery from Aerobic Granular Sludge and Conventional Flocculent Sludge in Treating Industrial Wastewater: Preliminary Analysis of Different Carbon Routes for Organic Carbon Utilization
- Author
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Francesco Traina, Santo Fabio Corsino, Michele Torregrossa, Gaspare Viviani, Traina Francesco, Corsino Santo Fabio, Torregrossa Michele, and Viviani Gaspare
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wastewater treatment ,sewage sludge ,Settore ICAR/03 - Ingegneria Sanitaria-Ambientale ,biopolymer ,circular economy ,aerobic granular sludge ,biopolymers ,extracellular polymeric substances ,polyhydroxyalkanoates ,Geography, Planning and Development ,polyhydroxyalkanoate ,Aquatic Science ,extracellular polymeric substance ,Biochemistry ,Water Science and Technology - Abstract
The recovery of biopolymers from sewage sludge could be a crucial step in implementing circular economy principles in wastewater treatment plants (WWTP). In this frame, the present study was aimed at evaluating the simultaneous production of polyhydroxyalkanoates (PHA) and extracellular polymeric substances (EPS) obtainable from the treatment of agro-industrial wastewater. Two biological enrichment systems, aerobic granular sludge (AGS) and a conventional activated sludge operating as a sequencing batch reactor (SBR), were monitored for 204 and 186 days, respectively. The maximum biopolymers accumulation capacity was close to 0.60 mgPHA-EPS gVSS−1 in the AGS when operating at 3 kgCODm−3d−1, whereas in the SBR, it was about half (0.35 mgPHA-EPS gVSS−1). Biopolymers extracted from the AGS were mainly constituted by EPS (>70%), whose percentage increased up to 95% with the OLR applied in the enrichment reactor. In contrast, SBR enabled obtaining a higher PHA production (50% of the biopolymers). Results suggested that organic carbon was mainly channeled toward metabolic pathways for extracellular storing in AGS, likely due to metabolic stressors (e.g., hydraulic selection pressure, shear forces) applied for promoting aerobic granulation.
- Published
- 2022
16. Membrane bioreactors for treatment of saline wastewater contaminated by hydrocarbons (diesel fuel): An experimental pilot plant case study.
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Mannina, Giorgio, Cosenza, Alida, Di Trapani, Daniele, Capodici, Marco, and Viviani, Gaspare
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BIOREACTORS , *SALINE waters , *HYDROCARBONS , *WASTEWATER treatment , *PILOT plants - Abstract
The paper reports the main results of an experimental campaign performed on a membrane bioreactor pilot plant designed to treat synthetic shipboard slops. The experimental campaign was divided into two phases: salinity acclimation up to 20 g NaCl L −1 (Phase I) and hydrocarbon (diesel fuel) dosing (Phase II). The observed results show that the carbon removal was not severely affected by the wastewater features. Conversely, respirometric tests showed that nitrification was strongly affected by the salinity (33% of nitrification efficiency at 20 g NaCl L −1 – Phase I) as a result of the salinity in the autotrophic biomass. Moreover, the sludge viscosity increased during Phase II due to the wastewater composition, leading to an increase in the membrane resistance, and severe degradation of the sludge dewaterability was also observed. Indeed, the capillary suction time increased by a factor of 3 times compared with that of Phase I. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
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