Maranon E.,University of Oviedo |
Castrillon L.,University of Oviedo |
Fernandez-Nava Y.,University of Oviedo |
Fernandez-Mendez A.,University of Oviedo |
Waste Management and Research | Year: 2010
The application of different coagulants and flocculants to leachate from an old landfill to determine the optimum conditions for removal of organic matter, colour and turbidity is studied. Ferric chloride, aluminium sulphate, aluminium polychloride (PAX) and polyacrylamide polyelectrolytes were tested. Higher pollutant removals (73% COD, 98% colour and 100% turbidity) were obtained using ferric chloride at pH 5.0-5.5 and for a dosage of 0.6 g Fe l- 1. The volume of sludge generated after centrifugation represents about 4.0-4.6% when ferric chloride or aluminium sulphate is used, and 10% when employing aluminium polychloride. When flocculants were also added, the results obtained were similar to those found when adding only coagulants, although a considerable increase in the settling rate was obtained. © The Author(s), 2010.
Garces D.,University of Oviedo |
Diaz E.,University of Oviedo |
Sastre H.,University of Oviedo |
Ordonez S.,University of Oviedo |
Waste Management | Year: 2015
Solid recovered fuels constitute a valuable alternative for the management of those non-hazardous waste fractions that cannot be recycled. The main purpose of this research is to assess the suitability of three different wastes from the landfill of the local waste management company (COGERSA), to be used as solid recovered fuels in a cement kiln near their facilities. The wastes analyzed were: End of life vehicles waste, packaging and bulky wastes. The study was carried out in two different periods of the year: November 2013 and April 2014. In order to characterize and classify these wastes as solid recovered fuels, they were separated into homogeneous fractions in order to determine different element components, such as plastics, cellulosic materials, packagings or textile compounds, and the elemental analysis (including chlorine content), heavy metal content and the heating value of each fraction were determined. The lower heating value of the waste fractions on wet basis varies between 10MJkg-1 and 42MJkg-1. One of the packaging wastes presents a very high chlorine content (6.3wt.%) due to the presence of polyvinylchloride from pipe fragments, being the other wastes below the established limits. Most of the wastes analyzed meet the heavy metals restrictions, except the fine fraction of the end of life vehicles waste. In addition, none of the wastes exceed the mercury limit content, which is one of the parameters considered for the solid recovered fuels classification. A comparison among the experimental higher heating values and empirical models that predict the heating value from the elemental analysis data was carried out. Finally, from the three wastes measured, the fine fraction of the end of life vehicles waste was discarded for its use as solid recovered fuels due to the lower heating value and its high heavy metals content. From the point of view of the heating value, the end of life vehicles waste was the most suitable residue with a lower heating value of 35.89MJkg-1, followed by the packaging waste and the bulky waste, respectively. When mixing the wastes studied a global waste was obtained, whose classification as solid recovered fuels was NCV 1 Cl 3 Hg 3. From the empirical models used for calculating higher heating value from elemental content, Scheurer-Kestner was the model that best fit the experimental data corresponding to the wastes collected in November 2013, whereas Chang equation was the most approximate to the experimental heating values for April 2014 fractions. This difference is due to higher chlorine content of the second batch of wastes, since Chang equation is the only one that incorporates the chlorine content. © 2015.