Estimation on the self recovery behavior of low-conductivity layer in landfill final cover by laboratory conductivity tests.
This study examined the application of a Self Recovering Sustainable Layer (SRSL) as a landfill final cover. Low-conductivity layers in landfill covers are known to have problems associated with cracking as a result of the differential settlement or climatic changes. A SRSL is defined as a layer with chemical properties that reduces the increased hydraulic conductivity resulting from cracking by forming low-conductivity precipitates of chemicals contained in the layer. In this study, the formation of precipitates was confirmed using a batch test, spectroscopic analysis and mineralogical speciation tests. The possibility of secondary contamination due to the chemicals used for recovery was evaluated using a leaching test. A laboratory conductivity test was performed on a single layer composed of each chemical as well as on a 2-layer system. The recovery performance of the SRSL was estimated by developing artificial cracks in the specimens and observing the change in hydraulic conductivity as a function of time. In the laboratory conductivity test, the hydraulic conductivity of a 2-layer system as well as those of the individual layers that comprise the 2-layer system was estimated. In addition sodium ash was found to enhance the reduction in conductivity. A significant increase in conductivity was observed after the cracks developed but this was reduced with time, which indicated that the SRSL has a proper recovering performance. In conclusion, a SRSL can be used as a landfill final cover that could maintain low-conductivity even after the serious damages due to settlement.
Kwon
O
O
Department of Civil Urban & Geosystem Eng., Seoul National University, Shinlim Dong, Gwanak Gu, Seoul, Korea, 151-742.
Park
J
J
D017610:Calcium Compounds / Q000737:chemistry; D011232:Chemical Precipitation; D003890:Desiccation; D007692:Diatomaceous Earth / Q000737:chemistry; D007723:Korea; D007753:Laboratories; D010087:Oxides / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D012822:Silicon Dioxide / Q000737:chemistry; D012987:Soil / Q000032:analysis*
D017610:Calcium Compounds; D010087:Oxides; D012987:Soil; C007886:granite; D007692:Diatomaceous Earth; C033787:diatomite; D012822:Silicon Dioxide; C016538:lime