Laboratory Sorption and Hydraulic Conductivity Tests: Evaluation of Modified-Clay Materials

Abstract

This study examines a new design philosophy for liner systems; that of controlling the hydraulic conductivity of leachate as a whole as well as retarding the advective and diffusive fluxes of pollutants by increasing the sorption of pollutants onto the liner systems. Claymax® (pure clay) and Organo-Clay (commercially available clays coated with organic amines) were evaluated as hydraulic barriers and as resistances to pollutant transport. Batch adsorption tests show that the removal capacity of lead by Claymax is 12-fold greater than that of Organo-Clay. However, the partition coefficients of a series of chlorobenzenes for Organo-Clay are 420-600 times greater than those for Claymax. The hydraulic conductivity of Claymax to tap water is at least two orders of magnitude lower than the value of 1 x 10^-7 cms^-1 for a clay liner required by the United States Environmental Protection Agency (EPA). Moreover, the hydraulic conductivity of Claymax with Organo-Clays is virtually unaffected when it is permeated with synthetic leachate. © 1996 ISWA

Keywords

Liner system hydraulic conductivity advection diffusion adsorption modified clay.

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References

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