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The capability of hydrodynamic cavitation (HC) of degrading organic pollutants in water effluents is evaluated through the implementation of an Artificial Neural Network (ANN) analysis. Thanks to the construction and training of a multilayer ANN, the energy efficiency of the process has been correlated to measurable variables. These last have been accurately chosen in order to propose a novel modeling approach in the field of HC water treatment. One of the main peculiarity of the proposed model is to choose the ANN input neurons among both operating variables and physical-chemical characteristics of the pollutants. In this way, a powerful tool for prediction, optimization and control of the process, is realized. Preliminary results on the ANN training and on the simulation of factor influences are presented.

The aim of the paper is to quantify and to compare the antiscalant effect of several additives on gypsum precipitation by measuring the retard on the induction period for nucleation. Through a well-assessed laser light scattering technique previously devised, the induction times are measured, and then used to estimate thermodynamic parameters such as the activation energy for nucleation, in a calcium sulfate supersaturated solution with the addition of NTMP, PBTC and citric acid. Experiments are carried out at a fixed additive concentration level (equal to 0.05 g/L), with the temperature varying in the range 15 – 35 °C. A comparison among different additives allows to define which is the most active in retarding gypsum scale formation.

This paper deals with the design and the preliminary optimization of the remediation of a Tetrachloroethylene (PCE)-contaminated aquifer by Pump and Treat technique (P&T) or Permeable Reactive Barrier (PRB). The experimental site is located near a solid waste landfill in the metropolitan area North of Naples (Italy) where a considerable amount of solid waste has been deposited over the past decades. For both remediation technologies, adsorption onto granular activated carbon was adopted to remove PCE from water. In particular, a comparison of the results obtained, both in terms of efficacy of pollutant removal and the corresponding preliminary overall cost, was conducted. The design of both remediation techniques was conducted by using a commercial 3D hydrodynamic code to simulate groundwater flow and contamination transport and a second code, developed by the authors, to describe the adsorption phenomena involving the pollutant.

This paper deals with the design and the preliminary optimization of the remediation of a . Tetrachloroethylene (PCE)-contaminated aquifer by Pump and Treat technique (P&T) or Permeable . Reactive Barrier (PRB). The experimental site is located near a solid waste landfill in the metropolitan area . North of Naples (Italy) where a considerable amount of solid waste has been deposited over the past . decades. For both remediation technologies, adsorption onto granular activated carbon was adopted to . remove PCE from water. In particular, a comparison of the results obtained, both in terms of efficacy of . pollutant removal and the corresponding preliminary overall cost, was conducted. The design of both . remediation techniques was conducted by using a commercial 3D hydrodynamic code to simulate . groundwater flow and contamination transport and a second code, developed by the authors, to describe . the adsorption phenomena involving the pollutant.

At ENEA-Trisaia research centre an inclined plug-flow type anaerobic digestor was coupled with an upgrading section consisting in a polymeric membrane, for biomethane production. The biogas produced by biomass and agroresidues fermentation is a mixture of different gases such as methane, carbon dioxide, hydrogen sulphide, nitrogen, hydrogen, mercaptans and oxygen. Low-pressure biogas membrane upgrading tests showed that at a pressure < 1 MPa biomethane recovery is over 50% (with a purity of about 70% v/v). High-pressure biogas membrane upgrading tests showed that at a pressure close to 3.0 MPa, it is possible to obtain a high purity biomethane stream with a CH4 concentration of about 99.5% v/v, but with a recovery of about 20% and CO2 selectivity < 1. A secondary membrane separation stage is required to overcome this problem allowing for an increased biomethane recovery keeping the purity unchanged. On this aspect further research work is necessary.

"\"This paper deals with the application of a Permeable Adsorbing Barrier (PAB) for the remediation of an aquifer contaminated by Tetrachloroethylene (PCE) and Trichloroethylene (TCE). Based on a hydrological and geotechnical characterization of the entire polluted aquifer, the design and optimization of the barrier parameters (location, orientation and dimensions) are defined by an iterative procedure using a CFD (Computational Fluid Dynamics) approach. Laboratory adsorption tests on binary system (i.e. PCE+TCE) on a commercial activated carbon are carried out to support the PAB design. A site located near a solid waste landfill in the metropolitan area North of Naples (Italy), where PCE and TCE are simultaneously present, is considered as a case study. Model results show that the PAB designed is effective for the remediation of the contaminated aquifer, both for single-compound and binary contamination, since the concentration of pollutants flowing out of the barrier is everywhere always lower than the concentration limits provided for Italian regulations on groundwater quality.\""

Adsorption on activated carbon is one of the most reliable and efficient technologies for the remediation of water polluted by heavy metals. In groundwater remediation, it actually found practical application in both pump-and-treat systems and permeable adsorbing barriers. One of the most significant limits to the practical adsorption of heavy metals in water streams is the absence of experimental data and modeling analysis coupling equilibrium and kinetic properties. In particular, kinetics and equilibrium results of hexavalent chromium adsorption onto activated carbon (AC) are significantly affected by ion speciation, which is made even more complex by the occurrence of reduction reactions on the AC surface. To the best of our knowledge, as at today reliable experimental data describing the mechanisms of chromium adsorption are still lacking as accurate supporting mathematical models for a proper design of industrial adsorbers are. In this work, the results of equilibrium and kinetic tests on the adsorption of chromium on a commercial granular AC are presented. Adsorption isotherms were determined in stirred batch reactors at different levels of pH, temperature and salinity. Kinetic tests were carried out in terms of breakthrough curves of a lab-scale fixed bed column at different levels of pH, inlet concentration and flow rate. Both the adsorption isotherms and the breakthrough curves showed non-linear and unconventional trends as a function of the main process parameters. The experimental results revealed that chromium speciation, in particular Cr(VI) reduction to Cr(III) reactions, played a key role in the adsorption process. Equilibrium tests were interpreted in light of a multi-component Langmuir model supported by the ions speciation analysis. Once the adsorption equilibrium assessed, it was possible to analyze the results of adsorption kinetics, so as to allow determining the mechanism that controls the adsorption rate in the investigated conditions.

"\"The most common commercial process for SO 2 removal from flue gas is the wet limestone flue gas . desulfurization process, in which sulfite oxidation represents an important limiting phenomenon. A detailed . knowledge of the oxidation process is important to determine the dewatering properties of the sludge . produced, and a good understanding of the oxidation kinetics is also useful for the development of . computer codes aimed at modeling the whole flue gas desulfurization process. Sulfite oxidation was . studied both in homogeneous conditions, obtained by contacting a sulfite solution with an oxygen . saturated solution, and in heterogeneous conditions, obtained by contacting a sulfurous solution with an . oxygen containing gas phase. As far as the bisulfite oxidation reaction in heterogeneous conditions is . concerned, a previous experimental study by the same research group in absolute catalyst free conditions . found a kinetic equation for calcium bisulfite oxidation which is of zero order in oxygen and three halves in . HSO 3. -. ions. The reaction has then been carried out in the presence of other catalysts, namely manganese . and ferrous ions, into a laboratory-scale well-mixed reactor. Experimental results have shown that, when . catalyst concentration increases, theree different reaction regimes (slow kinetic, slow diffusional and fast . reaction regime) can be detected. This paper proposes a numerical model to describe the interaction . between oxygen absorption and oxidation reaction, in which an in-parallel kinetic equation is used to . describe the slow kinetic reaction results, according to which the overall reaction rate can be calculated as . the sum of the uncatalyzed and catalyzed reaction rate, also taking into account that the oxidation kinetics . are zero order in oxygen. Moreover, this paper shows how the model is capable of describing the . experimental results obtained by this research group, as far as the manganese catalyzed bisulfite . oxidation rate is concerned. \""

The present work deals with the study of the adsorption of Trichloroethylene (TCE) onto a commercial granular activated carbon (GAC). Thermodynamic (batch) and dynamic (fixed-bed column) tests were carried out, under a wide range of operating conditions. In particular, adsorption isotherms were preliminary determined to support the investigation on a fixed-bed column at lab-scale. The main fluid dynamic and physical parameters such as flow rate, TCE concentration and GAC particle size were investigated. Experimental data on fixed-bed column show that an increase in TCE initial concentration and, more markedly, an increase in flow rate lead to a shorter breakpoint time. In fact, the breakthrough curves become steeper as a consequence of higher velocity that enhances the external mass transport. Finally, a thorough modeling analysis of the fixed-bed column was carried out using a model that includes axial dispersion and external-film diffusion followed by internal diffusion. A good accordance between experimental data and model results was observed.

"\"Emissions of unpleasant odours are associated to many different types of industrial . activities (e.g. paper mills, tanneries, refineries, slaughterhouses, distilleries, . pharmaceutical industries, etc.), civil and industrial wastewater treatment plants, landfills . and composting plants. Their production is generally related to microbial degradation . processes of putrescible organic substances. . In recent decades, the increasing number of landfills located in residential areas has . attracted the attention of the scientific and technical community, placing greater emphasis . on how odour emissions from landfills can be measured and how they can be diminished. . This paper proposes a Fuzzy Early Warning System (FEWS) for the mitigation of the risk . of exposure to odorous substances emitted from a waste landfill in a highly urbanised . area. A fuzzy logic approach was chosen to tackle the complex task of modelling an . automatic decision support system considering several risk variables, such as the wind . speed, the time derivative of the velocity, the wind direction, the time derivative of the . wind direction and the temperature. Indeed the fuzzy logic approach proved to be very . effective both for its “native” capability to deal with nonlinear models and for the possibility . to take into account heuristic and political rules. . The FEWS takes into account both hazard variables (e.g. the contaminant source . emission rate) and vulnerability and exposure variables (e.g. the distance of the landfill . and the typology of human activities). The case study of a solid waste landfill near Naples . (Italy), located in a densely populated area was considered. . The analysis of odour transport was carried out by using ISCST3-BREEZE developed by . EPA. This allows odour dispersion in air to be assessed as a function of weather . conditions (data provided by Capodichino Airport weather station) and contaminant . emissions (estimated using scientific literature). The FEWS is part of a MATLAB . framework in which the fuzzy input variables considered were modelled with a . “membership function” and the risk mitigation actions (e.g., covering of waste, spraying of . fragrant substances, extraction wells to maintain the landfill body at a pressure below . atmospheric, pressure, etc.) were inferred using a set of SUGENO fuzzy output rules. . The simulation results show that FEWS is very effective as compared to simulations . without any mitigation actions. Indeed the use of FEWS allowed for a considerable . reduction in the number of exceedances in all the sensitive centers analyzed, although in . some cases the FEWS operates also when it does not need. The next steps will consist . in improving the optimization of fuzzy rules and membership functions with other . techniques. \""

Refuse-derived fuel (RDF) steam gasification tests were performed in a rotary kiln pilot plant. The gas features were evaluated by varying the feeding ratio (FR), in the range 0.4-2.67, at a constant temperature equal to 850 °C. Several experimental tests were carried out in order to evaluate the best values for the main operating variables: kiln temperature, gas and solid residence time, etc., before evaluating the effect of the FR increase on the gas energy content and composition. Results show that the gas energy content decreases as the FR increases and, in the range of the FR studied, it achieves the maximum for FR=0.4, which corresponds to a volumetric gas composition of H 2 =59.1 %vv, CO=16.8 %v/v, CO 2 =20.1 %v/v, CH 4 =3 %v/v (not considering N 2 ) and the highest lower heating value (LHV) equal to 16 MJ kg gas -1 is obtained.

The growing awareness of the impact of environmental conditions on quality of life has led to the consideration of odours as atmospheric contaminants causing “olfactory pollution”. Odorous compounds do not directly represent a risk to human health; they are rarely dangerous in nature, not necessarily toxic, and generally found at low concentrations. Nevertheless it has been recognized that exposure to odours may cause different negative effects on human beings, ranging from emotional stress to physical symptoms. Consequently, when a system characterized by high emissions of odours is located in an urban context, its acceptance by the population is affected by its olfactory impact. This paper aims to assess the impact of odorous substances emitted from a landfill on the exposed population, by presenting a specific plant management methodology to minimize exposure to odours in terms of intensity and frequency. The results, evaluated for different percentiles, show that some residential areas may be affected by “olfactory harassment” if specific waste landfill management criteria are not applied. This methodology, if applied during the landfill design phase, may be a major tool for institutional decision-makers for comparing different options when choosing landfill sites.

La contaminazione delle falde acquifere da composti organo-clorurati è un problema particolarmente rilevante per gli alti livelli di concentrazione che spesso sono rilevati. Tali sostanze costituiscono un elevato rischio di tossicità per la salute umana ed animale e richiedono interventi di bonifica che, nella maggior parte dei casi, risultano essere molto costosi e complessi sia nella fase di progettazione che in quella di gestione. Le Barriere Permeabili Reattive Adsorbenti (PRB-A), possono essere una soluzione tecnicamente valida ed economica ma necessitano di studi più approfonditi su alcuni aspetti legati all’adsorbimento e all’ottimizzazione della forma e delle dimensioni. Lo scopo del seguente lavoro è quello di analizzare l’efficacia di una PRB-A nel trattamento di un acquifero nel caso di contaminazione multipla da Tetracloroetilene (PCE) e Tricloroetilene (TCE). A tal fine, è stato preso in esame, quale caso studio, un sito reale adibito a discarica. Le simulazioni realizzate con codici di calcolo dedicati hanno consentito di valutare l’evoluzione del plume di inquinante nello spazio e nel tempo, e di valutare l’efficacia delle PRB-A nel contenere al di sotto dei limiti normativi, la concentrazione di entrambi gli inquinanti studiati.

In virtù del crescente interesse per la. qualità dell’ambiente e della vita, gli odori molesti sono considerati veri e propri inquinanti atmosferici e si parla di “inquinamento olfattivo” per indicarne. l’impatto negativo sull'ambiente e sulla popolazione esposta. I composti odorosi non sono necessariamente tossici per la salute umana, ma è dimostrato che il benessere psicofisico e il comportamento. delle persone sono influenzati negativamente dall'esposizione agli odori. L’inserimento in un contesto urbanizzato di un impianto contraddistinto da notevoli emissioni di odori e la sua accettazione da parte della popolazione sono condizionati in misura sempre più rilevante dall'impatto olfattivo. Il seguente lavoro si propone di. valutare l’impatto delle sostanze odorigene emesse da una discarica controllata sulla popolazione. esposta, presentando una metodologia di conduzione dell’impianto atta a ridurre l’esposizione agli odori sia in termini di intensità che di frequenza.

Le emissioni di sostanze odorigene caratterizzano alcune attività produttive e fra queste, in particolar modo, quelle connesse con la gestione dei rifiuti biodegradabili. I composti odorosi non sono necessariamente un rischio per la salute umana, sia per la natura raramente pericolosa delle sostanze stesse che per le concentrazioni generalmente molto basse, tuttavia è stato dimostrato che il benessere psicofisico e il comportamento delle persone vengono influenzati negativamente dall'esposizione agli odori. Nel presente lavoro si riporta uno studio modellistico volto a valutare l'esposizione alle sostanze odorigene emesse da una discarica di rifiuti urbani inserita in un territorio ad elevata antropizzazione. Lo studio, condotto impiegando il software ISCT3-BREEZE e le informazioni meteorologiche reali su base oraria, ha consentito di valutare le frequenze, i livelli di esposizione e di fornire utili indicazioni per la mitigazione dell'esposizione.

In virtù del crescente interesse per la qualità dell’ambiente e della vita gli odori. molesti sono considerati veri e propri inquinanti atmosferici e si parla di“inquinamento olfattivo”. per indicarne l’impatto negativo sull'ambiente e sulla popolazione esposta. I composti odorosi. non sono necessariamente tossici per la salute umana ma è dimostrato che il benessere. psicofisico e il comportamento delle persone sono influenzati negativamente dall'esposizione. agli odori. L’inserimento in un contesto urbanizzato di un impianto contraddistinto da notevoli. emissioni di odori e la sua accettazione da parte della popolazione sono condizionati in misura. sempre più rilevante dall'impatto olfattivo. Questo lavoro si propone di valutare l’impatto delle. sostanze odorigene emesse da una discarica controllata sulla popolazione esposta, presentando. una metodologia di conduzione dell’impianto atta a ridurre l’esposizione agli odori sia in termini. di intensità che di frequenza."