Fly Ash as an Alternative Liner Material in Resloving Groundwater Management Challenges in Coal Ash Dumps
One of the key environmental challenges at electric power stations is leachate seepage from ash dumps into the underlying aquifers.Regulatory bodies generally recommend an installation of a liner system to contain toxic leachate at waste landfill sites.An attempt has been made in this study to enhance the engineering and geohydrological properties of fly ash in order for it to be used as a liner material.Varying quantities of lime and gypsum were added to fly ash in order to determine the optimum compositional ratio for the multi-layer liner system analysis.Addition of lime and gypsum increases the strength of fly ash.However this increase in strength was reduced when lime was used in excess.Addition of lime and gypsum decreases the hydraulic conductivity of fly ash.A hydraulic conductivity of 2.27×109 m/s was determined for an admixture of fly ash mixed with 3% lime and 3% gypsum.Mneralogical investigations revealed formation of secondary minerals in fly ash specimens that contained additives of lime and gypsum.These secondary minerals possibly reduced the effective porosity by clogging water pathways in the material.A water balance of the multi-layer liner system showed that 95% of leachate was contained by a fly ash admixture layer.Leachate analysed revealed that stabilization of fly ash with additives lowered concentration levels of some trace elements including chromium.
fly ash hydrogeochemistry groundwater management liner systems
Gideon Steyl Lehlohonolo Mokhahlane
Department of Chemistry, University of the Free State, South Africa and Golder Associates, Brisbane, Institute for Groundwater Studies, University of the Free State, South Africa
国际会议
The 12th Congress of International Mine Water Association,IMWA2014(第十二届国际矿井水大会)
徐州
英文
195-199
2014-08-18（万方平台首次上网日期，不代表论文的发表时间）