35 results on '"VIVIANI, Gaspare"'
Search Results
2. 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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Traina, Francesco, Corsino, Santo Fabio, Torregrossa, Michele, and Viviani, Gaspare
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SEWAGE ,INDUSTRIAL wastes ,CARBON analysis ,SEWAGE disposal plants ,BIOPOLYMERS ,ACTIVATED sludge process - 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−3 d−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. [ABSTRACT FROM AUTHOR]- Published
- 2023
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- View/download PDF
3. 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.
- Published
- 2016
4. 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.
- Published
- 2014
5. Global sensitivity analysis in ASM applications: comparison of the SRC and Extended-FAST method for a UCT-MBR model
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COSENZA, Alida, MANNINA, Giorgio, VIVIANI, Gaspare, Vanrolleghem, P, Neuwman, M., Cosenza, A, Mannina, G, Viviani, G, Vanrolleghem, P, and Neuwman, M
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Settore ICAR/03 - Ingegneria Sanitaria-Ambientale ,MBR modelling ,global sensitivity analysis ,Wastewater treatment - Abstract
In this study global sensitivity analysis is performed to identify influential as well as non-influential parameters in a model of a University Cape Town Membrane Bioreactor (UCT-MBR). In particular, the Standardised Regression Coefficients (SRC) and Extended-FAST sensitivity analysis methods are applied. The sensitivity of model variables towards parameter variation is analysed for CODTOT, SNH4, SNO3, SPO, and MLSS along five reactor compartments. Both methods indicate that the parameters identified as being influential differ from section to section due to the different processes involved. Moreover, the relevant influence of the membrane filtration parameters is detected in the first plant section due to the influence of the recycled sludge. It is found that the computationally less expensive SRC method is applied outside its range of applicability with R2 = (0.3-0.6) < 0.7. Nevertheless, the ranking obtained with the SRC method for the influential parameters is very similar to that of the Extended-FAST method, except for MLSS. However, to obtain reliable quantitative information on variance decomposition and to detect and quantify (in some cases considerable) interactions present among parameters the use of the computationally more expensive Extended-FAST is found to be necessary in this case study.
- Published
- 2011
6. Treatment of Oily Wastewater with Membrane Bioreactor Systems.
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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]
- Published
- 2017
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7. Radionuclides in wastewater treatment plants: monitoring of Sicilian plants.
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Cosenza, Alida, Rizzo, Salvatore, Santamaria, Antonio Sansone, and Viviani, Gaspare
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WASTEWATER treatment ,RADIOISOTOPES ,SCREENING in water purification ,SLUDGE conditioning ,WASTE management - Abstract
Three Sicilian wastewater treatment plants were monitored to assess the occurrence and the behaviour of radionuclides. Two sampling campaigns (screening and long-term) were carried out during which liquid and solid samples have been analysed. It was found that
131 I mostly occurred in the samples analysed during the screening campaign (43% of the analysed samples contained131 I). High131 I specific activity was found in the mixed liquor, recycled sludge and dehydrated sludge samples. This finding was mainly due to the tendency of131 I to be associated with solid particles. During the long-term sampling campaign an influence of the sludge retention time (SRT) on the131 I behaviour was found. Increasing the SRT and consequently decreasing the fraction of active organic biomass inside the system, the specific activity of131 I decreases. [ABSTRACT FROM AUTHOR]- Published
- 2015
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8. Quantification of kinetic parameters for heterotrophic bacteria via respirometry in a hybrid reactor.
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Di Trapani, Daniele, Mannina, Giorgio, Torregrossa, Michele, and Viviani, Gaspare
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WASTEWATER treatment ,BIOFILMS ,BIOREACTORS ,BIOMASS ,PLASTICS ,SEWAGE sludge ,MODIFICATIONS ,PILOT plants ,SEWAGE disposal plants - Abstract
Over the last decade new technologies are emerging even more for wastewater treatment. Among the new technologies, a recent possible solution regards Moving Bed Biofilm Reactors (MBBRs) that represent an effective alternative to conventional processes. More specifically such systems consist in the introduction of plastic elements inside the aerobic reactor as carrier material for the growth of attached biomass. Recently, one of the mostly used alternatives is to couple the Moving Bed Biofilm Reactor (MBBR) process with the conventional activated sludge process, and the resulting process is usually called HMBBR (Hybrid MBBR). In the MBBR process the biofilm grows attached on small plastic elements that are kept in constant motion throughout the entire volume of the reactor. Indeed, in such a system, a competition between the two biomasses, suspended and attached, can arise for the availability of the substrates, leading, as a consequence, to a modification in the biokinetic parameters of the two biomasses, compared to that of a pure suspended or attached biomass process. This paper presents the first results of a study aimed at estimating the kinetic heterotrophic constants in a HMBBR pilot plant using respirometric techniques. The pilot plant was built at the Acqua dei Corsari (Palermo) wastewater treatment plant and consisted of two parallel lines realized in a pre-anoxic scheme, in one of which the carrier material was added to the aerobic reactor with a filling ratio of 30%. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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9. Urban water quality modelling: a parsimonious holistic approach for a complex real case study.
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Freni, Gabriele, Mannina, Giorgio, and Viviani, Gaspare
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URBAN pollution ,WATER quality management ,WASTEWATER treatment ,WATER pollution ,MUNICIPAL water supply ,WATER quality ,SEWAGE purification ,URBAN watersheds ,POLLUTANT identification ,MANAGEMENT - Abstract
In the past three decades, scientific research has focused on the preservation of water resources, and in particular, on the polluting impact of urban areas on natural water bodies. One approach to this research has involved the development of tools to describe the phenomena that take place on the urban catchment during both wet and dry periods. Research has demonstrated the importance of the integrated analysis of all the transformation phases that characterise the delivery and treatment of urban water pollutants from source to outfall. With this aim, numerous integrated urban drainage models have been developed to analyse the fate of pollution from urban catchments to the final receiving waters, simulating several physical and chemical processes. Such modelling approaches require calibration, and for this reason, researchers have tried to address two opposing needs: the need for reliable representation of complex systems, and the need to employ parsimonious approaches to cope with the usually insufficient, especially for urban sources, water quality data. The present paper discusses the application of a bespoke model to a complex integrated catchment: the Nocella basin (Italy). This system is characterised by two main urban areas served by two wastewater treatment plants, and has a small river as the receiving water body. The paper describes the monitoring approach that was used for model calibration, presents some interesting considerations about the monitoring needs for integrated modelling applications, and provides initial results useful for identifying the most relevant polluting sources. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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10. Separate and combined sewer systems: a long-term modelling approach.
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Mannina, Giorgio and Viviani, Gaspare
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SANITARY sewer overflow , *SEWAGE purification , *SEWAGE disposal plants , *SEWERAGE , *WASTEWATER treatment , *WASTE management - Abstract
Sewer systems convey mostly dry weather flow, coming from domestic and industrial sanitary sewage as well as infiltration flow, and stormwater due to meteoric precipitations. Traditionally, in urban drainage two types of sewer systems are adopted: separate and combined sewers. The former convey dry and wet weather flow separately into two different networks, while the latter convey dry and wet weather flow together. Which is the best solution in terms of costbenefit analysis still remains a controversial subject. The present study was aimed at comparing the pollution loads discharged to receiving bodies by Wastewater Treatment Plant (WWTP) and Combined Sewer Overflow (CSO) for different kinds of sewer systems (combined and separate). To accomplish this objective, a comparison between the two systems was carried out using results from simulations of catchments characterised by different dimensions, population densities and water supply rate. The analysis was based on a parsimonious mathematical model able to simulate the sewer system as well as the WWTP during both dry and wet weather. The rain series employed for the simulations was six years long. Several pollutants, both dissolved and particulate, were modelled. The results confirmed the uncertainties in the choice of one system versus the other, emphasising the concept that case-by-case solutions have to be undertaken. Further, the compared systems showed different responses in terms of effectiveness in reducing the discharged mass to the RWB in relation to the particular pollutant taken into account. [ABSTRACT FROM AUTHOR]
- Published
- 2009
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11. 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]
- Published
- 2004
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12. 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]
- Published
- 2018
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13. 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]
- Published
- 2018
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14. Micropollutants throughout an integrated urban drainage model: Sensitivity and uncertainty analysis.
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Mannina, Giorgio, Cosenza, Alida, and Viviani, Gaspare
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MICROPOLLUTANTS , *SULFAMETHOXAZOLE , *WASTEWATER treatment , *DRAINAGE , *ENVIRONMENTAL impact analysis ,ENVIRONMENTAL aspects - Abstract
The paper presents the sensitivity and uncertainty analysis of an integrated urban drainage model which includes micropollutants. Specifically, a bespoke integrated model developed in previous studies has been modified in order to include the micropollutant assessment (namely, sulfamethoxazole – SMX). The model takes into account also the interactions between the three components of the system: sewer system (SS), wastewater treatment plant (WWTP) and receiving water body (RWB). The analysis has been applied to an experimental catchment nearby Palermo (Italy): the Nocella catchment. Overall, five scenarios, each characterized by different uncertainty combinations of sub-systems (i.e., SS, WWTP and RWB), have been considered applying, for the sensitivity analysis, the Extended-FAST method in order to select the key factors affecting the RWB quality and to design a reliable/useful experimental campaign. Results have demonstrated that sensitivity analysis is a powerful tool for increasing operator confidence in the modelling results. The approach adopted here can be used for blocking some non-identifiable factors, thus wisely modifying the structure of the model and reducing the related uncertainty. The model factors related to the SS have been found to be the most relevant factors affecting the SMX modeling in the RWB when all model factors (scenario 1) or model factors of SS (scenarios 2 and 3) are varied. If the only factors related to the WWTP are changed (scenarios 4 and 5), the SMX concentration in the RWB is mainly influenced (till to 95% influence of the total variance for S SMX,max ) by the aerobic sorption coefficient. A progressive uncertainty reduction from the upstream to downstream was found for the soluble fraction of SMX in the RWB. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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15. PHA and EPS production from industrial wastewater by conventional activated sludge, membrane bioreactor and aerobic granular sludge technologies: A comprehensive comparison.
- Author
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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]
- Published
- 2024
- Full Text
- View/download PDF
16. Modelling and dynamic simulation of hybrid moving bed biofilm reactors: Model concepts and application to a pilot plant
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Mannina, Giorgio, Trapani, Daniele Di, Viviani, Gaspare, and Ødegaard, Hallvard
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BIOFILMS , *PILOT plants , *SEWAGE sludge , *BIOMASS , *WASTEWATER treatment , *SIMULATION methods & models , *CHEMICAL reactors - Abstract
Abstract: In the recent years, there has been an increasing interest in the development of hybrid reactors, especially in the up-grading of existing activated sludge plants that are no longer able to comply with concentration limits established by regulatory agencies. In such systems the biomass grows both as suspended flocs and as biofilm. In this way, it is possible to obtain a higher biomass concentration in the reactor, but without any significant increase of the load to the final clarifier. The paper presents the setting-up of a dynamic mathematical model aimed at quantitatively describing the biokinetic processes occurring in a hybrid moving bed biofilm reactor (HMBBR), and, more in general, in integrated fixed-film activated sludge (IFAS) processes, as well as to compare the simulation results with measured data from a HMBBR pilot plant built at the Norwegian University of Science and Technology in Trondheim (Norway). Particularly, the pilot plant consisted of three aerobic tanks in series; the first and third aerobic reactors were pure suspended biomass systems, while the second aerobic reactor was filled with the AnoxKaldnes™ K1 carriers for biofilm development. The mathematical model consists of two connected models for the simulation of both suspended biomass and biofilm. Biochemical conversions are evaluated according to the well known matrix notation used in the Activated Sludge Model No. 1 (ASM1) for both attached and suspended biomass and, in addition to biochemical conversion, the model contains the simulation of particulate detachment from the biofilm into the bulk liquid. The results showed an overall good agreement between measured and simulated data, for both biofilm and suspended biomass, with a good reproduction of dynamic processes in the hybrid moving bed pilot plant, and they are encouraging for further developments. [Copyright &y& Elsevier]
- Published
- 2011
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17. 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]
- Published
- 2011
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18. Uncertainty assessment of an integrated urban drainage model
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Freni, Gabriele, Mannina, Giorgio, and Viviani, Gaspare
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MATHEMATICAL models , *DRAINAGE , *WASTEWATER treatment , *SEWERAGE , *WATER quality management , *WATERSHEDS , *CALIBRATION , *ESTIMATION theory - Abstract
Summary: Over the last few years, the use of mathematical models has gained importance in urban drainage system management; indeed, such models enable the combined analysis of different components that constitute a drainage system; the sewer system, wastewater treatment plant and the receiving water body. The effectiveness of an integrated approach has been widely demonstrated in the past and is presented in the EU Water Framework Directive, which also introduces a new point of view regarding the water quality management of the whole system, requiring a global analysis at the river basin scale for pollutant sources. However, integrated urban drainage models introduce several uncertain factors that are due to the high complexity level of the adopted approaches as well as to the lack of data for a robust model calibration. This paper presents the uncertainty assessment of an integrated urban drainage model developed in previous studies by means of the Generalized Likelihood Uncertainty Estimation methodology. The analysis has been applied to an experimental catchment in Bologna (Italy) which covers a part of the Bologna sewer network and a reach of the Savena River. [Copyright &y& Elsevier]
- Published
- 2009
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19. 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]
- Published
- 2008
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20. 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]
- Published
- 2024
- Full Text
- View/download PDF
21. Biological groundwater denitrification systems: Lab-scale trials aimed at nitrous oxide production and emission assessment.
- Author
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Capodici, Marco, Avona, Alessia, Laudicina, Vito Armando, and Viviani, Gaspare
- Subjects
- *
DENITRIFICATION , *BIOREACTORS , *NITRATES , *NITRIFICATION , *EMISSIONS (Air pollution) , *WASTEWATER treatment - Abstract
Bio-trenches are a sustainable option for treating nitrate contamination in groundwater. However, a possible side effect of this technology is the production of nitrous oxide, a greenhouse gas that can be found both dissolved in the liquid effluent as well as emitted as off gas. The aim of this study was to analyze NO 3 − removal and N 2 O production in lab-scale column trials. The column contained olive nut as organic carbon media. The experimental study was divided into three phases (I, II and III) each characterized by different inlet NO 3 − concentrations (30, 50, 75 mg NO 3 -N L −1 respectively). Sampling ports deployed along the length of the column allowed to observe the denitrification process as well as the formation and consumption of intermediate products, such as nitrite (NO 2 − ) and nitrous oxide (N 2 O). In particular, it was observed that N 2 O production represent only a small fraction of removed NO 3 − during Phase I and II, both for dissolved (0.007%) and emitted (0.003%) phase, and it was recorded a high denitrification efficiency, over 99%. Nevertheless, significantly higher values were recorded for Phase 3 concerning emitted phase (0.018%). This fact is due to increased inlet concentration which resulted in a carbon limitation and in a consequent decrease in denitrification efficiency (76%). [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
22. Aerobic granular sludge treating high strength citrus wastewater: Analysis of pH and organic loading rate effect on kinetics, performance and stability.
- Author
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Corsino, Santo Fabio, Di Trapani, Daniele, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
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
- Full Text
- View/download PDF
23. 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
- Subjects
- *
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
- Full Text
- View/download PDF
24. Physical properties and Extracellular Polymeric Substances pattern of aerobic granular sludge treating hypersaline wastewater.
- Author
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Corsino, Santo Fabio, Capodici, Marco, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
SLUDGE management , *CANNED fish industry , *WASTEWATER treatment , *SALINITY , *THRESHOLD energy - Abstract
The modification of the physical properties of aerobic granular sludge treating fish-canning wastewater is discussed in this paper. The structure and composition of the Extracellular Polymeric Substances (EPSs) were analyzed at different salinity levels and related to granules stability. Results outlined that the total EPSs content increased with salinity, despite the EPSs increment was not proportional to the salt concentration. Moreover, the EPSs structure was significantly modified by salinity, leading to a gradual increase of the not-bound EPSs fraction, which was close to the 50% of the total EPSs content at 75 g NaCl L −1 . The increasing salt concentration modified also the EPSs composition, causing the gradual reduction of protein content resulting in a decrease of granule hydrophobicity. The results pointed out that the granules stability significantly reduced above 50 g NaCl L −1 , suggesting the existence of a salinity threshold above which granules stability is compromised. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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- View/download PDF
25. Insights on mechanisms of excess sludge minimization in an oxic-settling-anaerobic process under different operating conditions and plant configurations.
- Author
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Corsino, Santo Fabio, Carabillò, Michele, Cosenza, Alida, De Marines, Federica, Di Trapani, Daniele, Traina, Francesco, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
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
- Full Text
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26. 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
- Subjects
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
27. Sequential batch membrane bio-reactor for wastewater treatment: The effect of increased salinity.
- Author
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Mannina, Giorgio, Capodici, Marco, Cosenza, Alida, Di Trapani, Daniele, and Viviani, Gaspare
- Subjects
- *
WASTEWATER treatment , *BATCH reactors , *BIOREACTORS , *SALINITY , *RESPIROMETERS - Abstract
In this work, a sequential batch membrane bioreactor pilot plant is investigated to analyze the effect of a gradual increase in salinity on carbon and nutrient removal, membrane fouling and biomass kinetic parameters. The salinity was increased by 2 g NaCl L −1 per week up to 10 g NaCl L −1 . The total COD removal efficiency was quite high (93%) throughout the experiment. A gradual biomass acclimation to the salinity level was observed during the experiment, highlighting the good recovery capabilities of the system. Nitrification was also influenced by the increase in salinity, with a slight decrease in nitrification efficiency (the lowest value was obtained at 10 g NaCl L −1 due to lower nitrifier activity). Irreversible cake deposition was the predominant fouling mechanism observed during the experiment. Respirometric tests exhibited a stress effect due to salinity, with a reduction in the respiration rates observed (from 8.85 mgO 2 L −1 h −1 to 4 mgO 2 L −1 h −1 ). [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
28. Membrane bioreactors for treatment of saline wastewater contaminated by hydrocarbons (diesel fuel): An experimental pilot plant case study.
- Author
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Mannina, Giorgio, Cosenza, Alida, Di Trapani, Daniele, Capodici, Marco, and Viviani, Gaspare
- Subjects
- *
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
29. Simultaneous nitritation–denitritation for the treatment of high-strength nitrogen in hypersaline wastewater by aerobic granular sludge.
- Author
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Corsino, Santo Fabio, Capodici, Marco, Morici, Claudia, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
BIOLOGICAL treatment of water , *NITROGEN in water , *WASTEWATER treatment , *AEROBIC bacteria , *CANNED fish industry , *NITRITES - Abstract
Fish processing industries produce wastewater containing high amounts of salt, organic matter and nitrogen. Biological treatment of such wastewaters could be problematic due to inhibitory effects exerted by high salinity levels. In detail, high salt concentrations lead to the accumulation of nitrite due to the inhibition of nitrite-oxidizing bacteria. The feasibility of performing simultaneous nitritation and denitritation in the treatment of fish canning wastewater by aerobic granular sludge was evaluated, and simultaneous nitritation–denitritation was successfully sustained at salinities up to 50 gNaCl L −1 , with a yield of over 90%. The total nitrogen concentration in the effluent was less than 10 mg L −1 at salinities up to 50 gNaCl L −1 . Nitritation collapsed above 50 gNaCl L −1 , and then, the only nitrogen removal mechanism was represented by heterotrophic synthesis. In contrast, organic matter removal was not affected by salinity but was instead affected by the organic loading rate (OLR). Both COD and BOD removal efficiencies were over 90%. The COD fractionation analysis indicated that aerobic granules were able to remove more than 95% of the particulate organic matter. Finally, results obtained in this work noted that aerobic granular sludge had an excellent ability to adapt under adverse environmental conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
30. Effect of C/N shock variation on the performances of a moving bed membrane bioreactor.
- Author
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Di Trapani, Daniele, Di Bella, Gaetano, Mannina, Giorgio, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
MEMBRANE reactors , *WASTEWATER treatment , *CARBON compounds , *NITRIFICATION , *AUTOTROPHIC bacteria , *CHEMICAL reduction - Abstract
The effect of a sharp variation of C/N ratio in a moving bed membrane bioreactor (MB-MBR) pilot plant treating high strength wastewater has been investigated. The experimental campaign was divided into two periods, each characterized by a different C/N ratio (namely, 2.5 and 15, Period 1 and Period 2, respectively). The MB-MBR system was analyzed in terms of organic carbon removal, nitrification efficiency, biokinetic activity and fouling behavior. The results showed that the nitrification process was severely affected by lower C/N value and by high concentration of ammonia. It was noticed an extensive stress effect on the autotrophic bacteria. Furthermore, it was observed an increase of the resistance related to particle deposition into membrane pores, likely due to a worsening of the cake layer features, with a reduction of the “pre-filter” effect, also related to the increase of the total Extracellular Polymeric Substances production with the C/N ratio. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
31. Comparison between moving bed-membrane bioreactor (MB-MBR) and membrane bioreactor (MBR) systems: Influence of wastewater salinity variation.
- Author
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Di Trapani, Daniele, Di Bella, Gaetano, Mannina, Giorgio, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
MOVING bed reactors , *MEMBRANE reactors , *BIOREACTORS , *WASTEWATER treatment , *SALINITY , *BIOMASS production , *RESPIROMETERS - Abstract
Highlights: [•] MBR and MB-MBR pilot plants under gradual salinity increase were compared. [•] Respirometry showed that the biomass activity was not significantly affected by the salinity. [•] Membrane fouling was mainly due to irreversible cake deposition. [•] Biofilm detachment phenomena affected the irreversible cake deposition. [•] Pore fouling tendency was more pronounced for the MBR pilot plant. [Copyright &y& Elsevier]
- Published
- 2014
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32. Performance of a MBR pilot plant treating high strength wastewater subject to salinity increase: Analysis of biomass activity and fouling behaviour.
- Author
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Di Bella, Gaetano, Di Trapani, Daniele, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
WASTEWATER treatment , *SALINE water conversion , *BIOMASS energy , *FOULING , *PERFORMANCE evaluation , *PILOT projects - Abstract
Highlights: [•] We examined a MBR pilot plant under high strength and saline wastewater. [•] Significant influence of salinity increase on nitrifying activity. [•] Membrane fouling mainly due to irreversible cake deposition. [•] Changes of biomass characteristics affected filtration properties. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
33. Performance of a hybrid activated sludge/biofilm process for wastewater treatment in a cold climate region: Influence of operating conditions.
- Author
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Di Trapani, Daniele, Christensson, Magnus, Torregrossa, Michele, Viviani, Gaspare, and Ødegaard, Hallvard
- Subjects
- *
ACTIVATED sludge process , *BIOFILMS , *WASTEWATER treatment , *AMMONIUM , *SOWING , *NITRIFICATION - Abstract
Highlights: [•] We examined a hybrid activated/biofilm pilot plant working in cold climate region. [•] High COD and ammonium removal efficiencies in the whole period. [•] It is possible to sustain nitrification at quite low SRT values of mixed liquor. [•] Seeding effect of nitrifiers from the detached biofilm to the mixed liquor. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
34. Evaluation of biomass activity and wastewater characterization in a UCT-MBR pilot plant by means of respirometric techniques
- Author
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Di Trapani, Daniele, Capodici, Marco, Cosenza, Alida, Di Bella, Gaetano, Mannina, Giorgio, Torregrossa, Michele, and Viviani, Gaspare
- Subjects
- *
BIOMASS energy , *BIOREACTORS , *MEMBRANE reactors , *WASTEWATER treatment , *SEWAGE disposal plants , *MATHEMATICAL models , *CHEMICAL kinetics , *PLANT nutrients - Abstract
Abstract: Over the last two decades, Membrane Bioreactors (MBRs) emerged even more for wastewater treatment, ensuring high removal efficiencies as well as very small footprint requirements. Indeed, in this kind of process, a modification in biomass activity and viability can exist compared to that of a CAS process. In this context, respirometric analysis represents a reliable tool in order to evaluate the actual biomass kinetic parameters, to insert in mathematical models in the design phase, as well as to monitor the biomass viability, especially when these processes are operated with high SRT values. The paper presents some results of respirometric techniques applied for the characterisation of wastewater and biomass activity in a pilot UCT-MBR plant for nutrient removal, operating with high SRT. In particular, the respirometric tests were specifically aimed at investigating heterotrophic and autotrophic bacterial activity. The pilot plant was built at Palermo WWTP and consisted of three reactors: anaerobic, anoxic and aerobic, followed by an aerobic compartment containing two submerged hollow fibre membrane modules with typical recycling lines. The kinetic parameters for heterotrophic bacteria resulted lower respect to the CAS; regarding the nitrifying bacteria, the kinetic constants were in the range of CAS, suggesting a good nitrification activity. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
35. Achievement of partial nitrification under different carbon-to-nitrogen ratio and ammonia loading rate for the co-treatment of landfill leachate with municipal wastewater.
- Author
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Capodici, Marco, Corsino, Santo Fabio, Di Trapani, Daniele, and Viviani, Gaspare
- Subjects
- *
LEACHATE , *NITRIFICATION , *WASTEWATER treatment , *LANDFILL management , *AMMONIA , *LANDFILLS , *BATCH reactors - Abstract
• PN process was studied in a SBR treating landfill leachate at different ALR and C/N. • Stable PN was achieved at ALR between 0.30-0.50 kg NH 4 -N m−3d-1 and C/N lower than 4. • NOB inhibition was achieved at lower ALR and higher C/N compared with the literature. • The highest PN and TN removal performances were obtained under similar ALR and C/N. • The maximum autotrophic activity was found at ALR of 0.30 kg NH 4 -N m−3d-1. Partial nitrification (PN) is a technically and economically effective solution for the treatment of wastewater featuring low C/N ratio, allowing to achieve approximately 25% energy saving and 40% carbon source for denitrification. This study investigated the effect of different carbon to nitrogen ratio (C/N) and ammonia loading rate (ALR) on PN performances in a sequencing batch reactor (SBR) treating landfill leachate with municipal wastewater. The aim was to find an optimum range for C/N and ALR to maximize PN performances. Results demonstrated that a proper balancing between ALR and C/N is crucial to achieve high PN efficiency. The results highlighted the existence of an optimum range for ALR and C/N of approximately 0.30–0.50 kg NH 4 -N m−3d−1 and 2–4, respectively. Although complete suppression of NOB was not achieved at these values, a predominance of nitrite (125 mg L−1) to nitrate (50 mg L−1) was observed. The results demonstrated the achievement of PN even at high C/N (4) but, on the other hand, C/N higher than 6 were not favorable to autotrophic growth. C/N significantly lower than 4 caused a stress condition for the biomass, leading to an excess in SMP production. Therefore, the operational parameters as well as the co-treatment ratio should be adjusted in order to operate the system under specific ALR (0.30–0.50 kg NH 4 -N m−3 d−1) and C/N (2–4). [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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