Browsing by Author "Erses, Aliye Suna."

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    In situ immobilization of the selected heavy metals by sulfide compounds in landfills under methanogenetic conditons
    (Thesis (M.S.) - Bogazici University. Institute of Environmental Sciences, 2001., 2001.) Erses, Aliye Suna.; Onay, Turgut T.
    Co-disposal is a technique for the controlled disposal of hazardous wastes together with municipal solid waste. Co-disposal of industrial wastes including heavy metals and disposal of household hazardous substances such as batteries, paints, dyes and inks -in paper result in release of heavy metals into a landfill environment. Zinc, iron, nickel, copper and cadmium are the most common heavy metals disposed to landfills. These metals are controlled by several attenuation mechanisms including adsorption, acid-base, oxidation-reduction and precipitation-complexation reactions. This research aimed to better understand the extent of heavy metal attenuation in landfills by means of precipitation by sulfide compounds. The effect of selected heavy metals (Zn, Cu, Cd, Fe, Ni) on solid waste stabilization together with the effect of leachate recirculation on the attenuation mechanisms was also investigated. For this purpose, two landfill simulating reactors were used in the laboratory. These reactors were constructed and filled with shredded and compacted municipal solid waste having typical solid waste composition determined for istanbul region. Two reactors, one with leachate recirculation, the other without were operated in the constant temperature room of 32°C to enhance the growth of anaerobic microorganisms. Moreover, moisture addition was done into the reactors in order to simulate the annual rainfall. After the onset of the methanogenetic conditions in both reactors, the selected heavy metals including iron, copper, nickel, cadmium and zinc were added into the simulated landfill reactors. The metals (Fe, Cu, Ni, Cd, Zn ) were prepared by dissolving the metal salts in one liter deionized water and introduced into the bioreactors according to the amounts suggested for co-disposal under the directives of the Turkish Hazardous Waste Control Regulations to prevent inhibition of the microbially mediated processes during waste stabilization This research indicated that when sulfide concentration was very low or insufficient, the removal of the metals was controlled by other anions such as C03 = and P04- 3 until the reduction of sulfate coming from loaded metal salts into the reactors Moreover, leachate recirculation offers opportunities for more rapid waste stabilization including attenuation of co-disposed heavy metals.
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    Sustainable solid waste management and in-situ attenuation mechanisms in landfills under aerobic and anaerobic conditions
    (Thesis (Ph.D.)-Bogazici University. Institute of Environmental Sciences, 2008., 2008.) Erses, Aliye Suna.; Onay, Turgut T.
    The objective of this study was to obtain information about aerobic and combination of aerobic and anaerobic digestion of solid waste in landfills in order to evaluate and determine an efficient and cost-effective landfill management system. The proposed research was focus mainly on to find optimal conditions for solid waste degradation and better understand the attenuation mechanisms for carbon, nitrogen, sulfur and heavy metal by using aerobic, anaerobic, aerobic pretreated and aerobic remediated landfill concepts. With this goal, four landfill bioreactors were operated under aerobic and anaerobic conditions in a thermo-insulated room at a constant temperature of 32 ºC. Reactors were filled with the shredded synthetic solid waste of 19.5 kg prepared according to the average municipal solid waste compositions determined in İstanbul and operated under wet-tomb management strategy by using leachate recirculation. Aerobic conditions in the reactor were developed by using an air compressor. The results of this study showed that aeration in municipal solid waste landfills is a viable management option for the accelerated stabilization of a waste matrix. Aeration is a feasible way to treat the leachate in situ, and, therefore, decrease the cost of further external treatment. Aeration of the waste mass provides rapid removal of organics, nitrogen and phosphorus. Aerobic pretreated and aerobic remediated bioreactor landfill concepts were also more efficient in terms of waste stabilization and leachate treatment when compared to the anaerobic bioreactor.|Keyword: Areobic landfilling, anaerobic landfilling, municipal solid waste, bioreactor, leachate recycle