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A plant, designed for the thermo-valorisation of tyres, was specifically modified in order to treat Automobile Shredder Residue (ASR). Results from two full-scale combustion experiments, carried out on large ASR feeding lots (thousands of tons) indicate the proposed technology as a potential route to help the fulfilling of impending 95% reuse and recovery target set by the End of life Vehicle (ELV) Directive (January 2015). The paper describes the main operational troubleshot occurred during the first experiment (emissions at the stack out of regulatory limits and problems of clogging on the conveyer belt) and the consequent upgrading solutions (pre-treatment, introduction of waste double low-flow screw feeder and a cyclone prior to the main fan, modification of rotatory kiln inlet) adopted to allow, during the second long-term experiment, a continuous basis operation of the plant in full compliance with the discharge limit to the atmosphere. Characterization of both ASR and combustion residues allowed to quantify a 18% of combustion residues as not dangerous waste while only the 2% as hazardous one. A pre-treatment for the reduction of fines in the ASR was recommended in order to achieve the required energy recovery efficiency. [ABSTRACT FROM AUTHOR]

Abstract: In order to obtain 85% recycling, several procedures on Automotive Shredder Residue (ASR) could be implemented, such as advanced metal and polymer recovery, mechanical recycling, pyrolysis, the direct use of ASR in the cement industry, and/or the direct use of ASR as a secondary raw material. However, many of these recovery options appear to be limited, due to the possible low acceptability of ASR based products on the market. The recovery of bottom ash and slag after an ASR thermal treatment is an option that is not usually considered in most countries (e.g. Italy) due to the excessive amount of contaminants, especially metals. The purpose of this paper is to provide information on the characteristics of ASR and its full-scale incineration residues. Experiments have been carried out, in two different experimental campaigns, in a full-scale tyre incineration plant specifically modified to treat ASR waste. Detailed analysis of ASR samples and combustion residues were carried out and compared with literature data. On the basis of the analytical results, the slag and bottom ash from the combustion process have been classified as non-hazardous wastes, according to the EU waste acceptance criteria (WAC), and therefore after further tests could be used in future in the construction industry. It has also been concluded that ASR bottom ash (EWC – European Waste Catalogue – code 19 01 12) could be landfilled in SNRHW (stabilized non-reactive hazardous waste) cells or used as raw material for road construction, with or without further treatment for the removal of heavy metals. In the case of fly ash from boiler or Air Pollution Control (APC) residues, it has been found that the Cd, Pb and Zn concentrations exceeded regulatory leaching test limits therefore their removal, or a stabilization process, would be essential prior to landfilling the use of these residues as construction material. [Copyright &y& Elsevier]

Abstract: In this paper, lab tests coupled to a semi-pilot test section are used to derive data for the calibration of a numerical model. The paper is aimed at proposing a set of experiments, which can be used to calibrate a numerical model before using it on defined soils. The complexity of the phenomenon of transport of reactive pollutants in soil has to be faced in the most complete way. The different behaviour of soil after wet/dry cycles with respect to the fluidodynamic characteristics and the importance to consider the local biomass behaviour in case of organic contaminant has been underlined. An optimal approach has to take into account all the different components and here a simple series of experimental procedure is presented. The sensitivity analysis of the numerical model has shown that its results are not so much dependent on the classical numerical aspects (time or space increments) but mainly on a set of parameters related to soil structure which must then be derived through a good calibration. [Copyright &y& Elsevier]

Biofiltration is gradually gaining popularity among biological wastewater treatment processes, becoming a valid alternative to the more widespread activated sludge system. In order to understand better the operating conditions that influence the efficiency of such a process, a mathematical model has been developed. It allows the calculation of the COD and N-NH4+ profiles along the filter height and inside the biofilm and simulates filter clogging due to the biomass growth. The model output has been verified through a series of sensitivity tests and its results have been calibrated considering the results of an experimental campaign conducted on the Biostyr® biofiltration unit of the Rome southern municipal wastewater treatment plant. Such a model can be used to understand better the influence of variation of the operating conditions on the efficiency of the biofiltration process, furthermore representing a valid predictive tool for the management of existing wastewater treatment plants and for the design of new ones. [Copyright &y& Elsevier]

Urban air pollution is a growing problem. Large cities in particular show, at some point of time, high concentrations of substances dangerous for human health. The difficulty in forecasting pollutant''s concentration trends with a reasonable error is still an open problem. In this paper, a new approach is proposed. An artificial neural network (ANN) is used to forecast short and middle long-term concentration levels for some of the well-known pollutants. The results seem to be in good accord with the monitored data and allow its use as the forecasting model on a 24–48 h basis requiring only the meteorological conditions and the traffic level. [Copyright &y& Elsevier]

This work presents the results of a comparison of three different management scenarios (one current and two future) of waste, wastewater, and their related energy systems in Southern European regions. A Life Cycle Assessment (LCA) has been applied to all the different steps of the complex scenarios in order to provide a more holistic, robust, and scientific approach that is able to highlight the beneficial effects of the integration of different plants (Waste to Energy - WtE, Anaerobic digestion - AD, wastewater treatment plant - WWTP) included in a symbiotic nexus. The LCA results have shown that an important reduction in the impact of Municipal Solid Waste (MSW) management is obtained from the recovery of separately collected materials, but there is still a large gap that could be filled by the introduction of energy recovery (by means of AD and WtE) and through its symbiotic use to support the anaerobic digestion, wastewater reuse, and sludge recovery processes. The proposed approach, which is based on a waste-wastewater-energy nexus and industrial symbiosis, could be adopted to support these regions to significantly increase circularity and fill the gap, thus favoring a significant rapprochement in the path toward the New Green Deal promoted by the European Union. • The contribution of Industrial Symbiosis within the Waste-wastewater-energy nexus is presented. • An innovative role of WtE plant within circular economy is identified. • LCA indicators are clearly associated with well-defined material and energy balances. • The results can improve the overall sustainability in waste-wastewater integrated management in several areas of the world. [ABSTRACT FROM AUTHOR]

Abstract: Until only recently fluff has been largely disposed of in controlled landfill sites. However, in Europe environmental regulations, including the EU Landfill Directive 1999/31/EC and ELV (End of Life Vehicle) Directive 2000/53/EC, have dramatically increased the pressure on all stakeholders to develop alternative solutions. As increasingly stringent legislation forces Shredder Residues (SR) to be diverted from landfilling, newly developed technologies will be in a position to compete for the market value of disposing of the waste. However, the fluff waste stream is so variable that it cannot be automatically assumed that processes developed for one type of fluff will prove to be suitable for other fluff streams. This situation has contributed towards convincing stakeholders to withhold investment funds or delay taking decisions as to how best to proceed; as a consequence, very few technologies have been fully developed on a commercial basis. It is of particular interest therefore that commercial alternatives to be used in dealing with this complex waste stream should be identified. The present paper illustrates the findings of a full-scale thermal treatment performed on SR samples obtained from various shredding plants. The outcome of the study provides an important contribution towards assessing the feasibility and reliability of the process, thus constituting a basic prerequisite for process performance evaluation. The full-scale plant, designed for the thermo-valorization of tyres, was purpose-modified to allow for fluff combustion. Three different fluff compositions (car fluff with different percentage of shredding, whites and 100% car fluff) were taken into consideration. Both the raw samples and solid products were thoroughly characterized. Combustion emissions were continuously analyzed during the test period, alternatively operating for tyre and fluff combustion. Classification of combustion residues for landfill disposal was carried out indicating only 2% (ashes) as hazardous waste. Preliminary results, obtained from a unsophisticated thermodynamic analysis of the process, indicated a value of 0.61 for energy efficiency parameter calculated in accordance with the Directive 2008/98/EC. To conclude, the thermal treatment investigated may be deemed an appropriate technique for use in managing fluff. Indeed, values obtained for all organic and inorganic contaminants released into the atmosphere were lower than legal limits prescribed, and a significant energy content was recovered from waste fractions. [Copyright &y& Elsevier]

Automotive Shredder Residue (ASR) is a special waste that can be classified as either hazardous or non hazardous depending on the amount of hazardous substances and on the features of leachate gathered from EN12457/2 test. However both the strict regulation concerning landfills and the EU targets related to End-of-Life Vehicles (ELVs) recovery and recycling rate to achieve by 2015 (Directive 2000/53/EC), will limit current landfilling practice and will impose an increased efficiency of ELVs valorization. The present paper considers ELVs context in Italy, taking into account ASRs physical–chemical features and current processing practice, focusing on the enhancement of secondary materials recovery. The application in waste-to-energy plants, cement kilns or metallurgical processes is also analyzed, with a particular attention to the possible connected environmental impacts. Pyrolysis and gasification are considered as emerging technologies although the only use of ASR is debatable; its mixing with other waste streams is gradually being applied in commercial processes. The environmental impacts of the processes are acceptable, but more supporting data are needed and the advantage over (co-)incineration remains to be proven. [ABSTRACT FROM AUTHOR]

Abstract: Existing models for H2 production are capable of predicting digester failure caused by a specific disturbance. However, they are based on studies using simple sugars, while it is known that H2 production and fermentation kinetics vary with the composition and characteristics of the substrate used. Because the behaviour of biological processes may differ significantly when the digesting material is a complex matrix, such as organic waste, the aim of this study was to develop and calibrate a mathematical model for the prediction of hydrogen production on the basis of the results obtained from a laboratory scale experimental study using source-selected organic waste. The calibration was carried out for the most important kinetic parameters in mesophilic anaerobic digestion processes and also served as a sensitivity analysis for the influence of both the specific growth rate (μmax and the half velocity constant (ks ), both of which are strongly dependant on the substrate used. High values of μmax led to a shorter lag-time and to an overestimate of the cumulative final H2 production relative to the experimentally measured production. Additionally, high values of ks associated with amino acid and sugar fermentation corresponded to a lower rate of substrate consumption and to a greater lag-time for growth of hydrogen-producing microorganisms. In this case, a lower final H2 production was predicted than that which was experimentally observed. Because the model development and calibration provided useful information concerning the role of the kinetic constants in the analysis of a fermentative H2 production process from organic wastes, they may also represent a good foundation for the analysis of fermentative H2 production from organic waste for pilot and full-scale applications. [Copyright &y& Elsevier]

The aim of the present work was to evaluate the performance of a pilot-scale BAF in terms of removal of organic matter and suspended solids to obtain a highly polished effluent. The first part of the research was the evaluation of the optimal filter media for a full scale BAF. Mechanical and biological tests were performed over four materials: glass, plastic, pozzolan and expanded clay (Arlita) and the results obtained showed that the plastic spheres and the Arlita particles were the optimal materials for both the mechanical and biological requirements. Hence, a down-flow pilot scale BAF was set up in the laboratory to treat a synthetic medium. As filter media first plastic spheres and then Arlita spheres were used. Carbon removal studies were carried out at several influent COD concentrations, specific removal efficiency and COD profiles along the height of the filter were determined and used to analyze the process. Validation and calibration of a mathematical model formulated for carbon removal, were also performed by using the experimental data obtained. The results showed that this system allows us to achieve the more strict limits on final effluent. [ABSTRACT FROM AUTHOR]

The present paper discusses issues, scenarios, new ideas and processes with the specific purpose of quantitatively evaluating the feasibility of applying industrial symbiosis (IS) to regions where Waste-to-Energy (WtE) processes are not fully utilised (e.g. many Mediterranean regions), in order to exploit the potential synergies between 1) wastewater treatment (WWT), 2) WtE and 3) Anaerobic Digestion (AD) processes in a new, holistic approach that is able to maximise the efficient use of resources, while reducing the current environmental impacts. The enormous energy that can be obtained from residual waste is partially used, through an IS-based biorefinery approach, to thermally support the AD and drying processes of organic waste and sludge, thereby allowing 100% of the increased biogas production to be upgraded to biomethane. The need to landfill can be reduced to less than 5–10%, which allows the 2035 EU target to be achieved, with relevant economic and environmental benefits. Electricity from the WtE plant is exploited to supply the utilities of the 3 main processes and in particular to lower the costs of the required tertiary WWT and wastewater pumping phases in order to make the reclaimed water cost competitive with that of conventional water resources and thus to make this marginal water resource fully sustainable. The proposed approach can be applied in numerous countries, where landfilling is still predominant, to help stakeholders favouring a cultural shift towards a more sustainable, integrated waste/wastewater management while lowering the sterile "Not In Anyone's BackYard" (NIABY) opposition to WtE plants. Image 1 • The industrial symbiosis (IS) scenario allows the 2035 EU landfill target (<10%) to be achieved. • The IS based scenario increases biogas production from OF-MSW and WWTP sludge. • Through the IS-based biorefinery approach, 100% of the biogas can be upgraded to biomethane. • Only the IS scenario allows a positive energy balance to achieve 100% wastewater reuse. • The IS approach can lead to a cultural shift in waste/wastewater management and lower the NIABY syndrome. [ABSTRACT FROM AUTHOR]

The present paper compares the experimental results obtained from a research programme developed on a pilot-scale fluidized bed biofilm reactor and the outputs of a numeric simulation model; the mathematical model can determine the substrate concentration profile within the reactor. The experimental campaign investigated heterotrophic biological denitrification in anoxic conditions. The model is based on multi-substrate Michaelis-Menten kinetics and considers mass transport resistance p phenomena a within and outside bioparticles. A monodimensional model of the reactor taking into consideration, in steady-state condition, phenomena due to convective transport and turbulent diffusion has been used. The fluidization model applied to describe the behaviour of the biofilm-covered rigid particle bed is based on the Wen and Yu correlation. [ABSTRACT FROM AUTHOR]