Analysis of di usion-adsorption equivalency of landfill liner systems fororganic contaminants
XIE Haijian , CHEN Yunmin , KE Han , TANG Xiaowu , CHEN Renpeng
DOI:
Received February 07, 2008,Revised May 05, 2008, Accepted , Available online
Volume 21,2009,Pages 552-560
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The equivalence between multilayered barriers regarding di usion and adsorption was studied. The bottom boundary of the liner
system is defined by assuming concentration continuous and flux continuous conditions of the contaminant between the bottom liner
layer and the underlying soil. Five di erent liner systems were compared in terms of solute breakthrough time. The results of the
analysis showed that breakthrough time of the hydrophobic organic compounds for a 2-meter-thick compacted clay liner (CCL) could
be 3–4 orders of magnitude is greater than the breakthrough time for a geosynthetic clay liner (GCL) composite liner. The GM/GCL and
GM/CCL composite liner systems provide a better di usion barrier for the hydrophilic organic compounds than that for the hydrophobic
compounds due to their di erent Henry’s coe cient. The calculated breakthrough times of the organic contaminants for the Chinese
standard liner systems were found to be generally greater than those for the GCL alternatives, for the specific conditions examined.
If the distribution coe cient increases to 2.8 for the hydrophobic compounds or 1.0 for the hydrophilic compounds, the thickness of
the attenuation layer needed to achieve the same breakthrough time as the standard liner systems can be reduced by a factor of about
1.9–2.4. As far as di usive and adsorption contaminant transport are concerned, GM or GCL is less e ective than CCL.
