1,721,138 research outputs found
Evoluzione della sostanza organica nel percolato di discariche per rifiuti industriali
No full textWe examine the results of the characterization made on two MSWI bottom ash release test carried out on sample representative of 6 months of plant operation. Beyond the mineralogical, chemical, and particle-size characterization, we investigate in detail the release of heavy metals, both by first level characterization with pH static-test and by II level compliance test. The release was estimated also on the single dimensional class fraction. The behaviour of two ashes is similar and the influence of different total metals quantity is sensible only at the extreme values of pH. The effect of the pH is much obvious for the amphoteric metals (Al, Pb, Zn) whereas the particle size is the only macroscopic factor that influence the release of Cu. The final pH of the leachate is function of the dimensional class considered and the leaching test. We even observe some change in the release with distilled water (test UNI 10802) between the humid ash, as taken just after quenching in water, and the ash let exposed to the air for a time in between some hours to weeks. For the lead there is a strong drop of the final concentration in the leachate. We interpret this effect with carbonation of the bottom as
Maturazione in cumulo all'aperto di scorie pesanti derivanti dall'incenerimento di RSU
No full textMaturation test were carried out on heaps of MSWI bottom ash. The testing was carried out over a sixmonth period in autumn and winter. The aim was to verify, in a pilot plant, the feasibility of the maturation process in relation to a reduction of the release of lead in the aqueous phase within normative limits for landfill. The evolution of the maturation mechanism has been studied in function of time, characteristics of the ashes, and behaviour according to Italian conformity test UNI 10802. To estimate the influence of weather and preparation, heaps were prepared with different heights using both untreated ash and ash after sieving, in both exposed and covered heaps. During the testing period the release of lead, cooper, chlorides, conductivity, pH, alkalinity, calcium, sulphates, DOC were measure. Coupling this test with the meteorological data, it was possible to characterize the physical and chemical mechanisms involved in the maturation and to verify the role of hydroxide carbonatation and its controlling factors. The results have made possible to define outlines to optimise the treatment. We suggest a maturation period in heaps of untreated ash, then sieving and recovery of the iron and finally a second period of post maturation of the sieved ashes (< 30 mm
Test di laboratorio per la valutazione preliminare dell'efficienza del ferro zero-valente per il trattamento di acque acide di miniera
No full text
Emissione di metalli con le polveri sedimentabili da una discarica per rifiuti industriali
No full textResults of atmospheric dispersion model for the localization of a MSW incinerator
No full textThe present study reports the attempt to localize a MSW incinerator, starting from three proposed sites, on the basis of the atmospheric transport and dispersion modelling. The considered area, around Turin, in North-Western Italy, is characterized by a high percentage of hours of calm wind, so the choice of the atmospheric model is very important in order to have reliable and convincing results. In the present study we used the AERMOD model by the U.S. EPA, that is a hybrid atmospheric dispersion model which can treat the calm hours within a more restrained computational time with respect to Eulerian or Lagrangian models. The investigated issue is generally a very delicate and thorny argument because of the natural opposition of the people against this kind of plant. The first thing to do to treat the localization of a MSW incinerator is to calculate the concentrations at the ground level due to the emitted pollutants and to compare them to the air quality regulations; secondly, one can think about the possibility of building a district heating system or distributing technological vapour service to industrial users, avoiding the respective emission of pollutants. In practice, the concentrations at the ground level when the incinerator is placed in the three proposed sites are very comparable and, for each site, much smaller than the air quality regulations and the measured levels of the area. The best localization is then determined by the possibility of realising a large district heating system
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