LANDFILL SEALING POTENTIALS OF BOTTOM ASHES OF SLUDGE CAKES

The main objective of this study is to determine if bottom ashes of dr ied sludge cakes (SCbash) could be used as landfill cover or liner, a function which is normally performed with clay. Laboratory tests were performed to determine its particle size distribution, Atterberg limit s, compaction characteristics, hydraulic conductivity, and shear stren gth parameters. The effects of desiccation and freeze-thaw on the hydr aulic conductivity of SCbash were also examined. The results of this i nvestigation proved that properly compacted and stabilized SCbash has the required properties to be used in landfill covers or Liners. The S Cbash can be compacted into a dense mass with a low hydraulic conducti vity of the order of 1.15x10(-7) m/s. The compacted SCbash showed also a good resistance to the increase in hydraulic conductivity caused by desiccation and freeze-thaw as compared to other compacted clays. The results also indicated that the compacted SCbash has greater shear st rength as typically expected for compacted clay, and therefore is like ly to remain stable on a typical landfill slope designed and based on clay shear strength. (C) 1998 Elsevier Science B.V. All rights reserve d.