Evaluation of Organoclays for Use in Landfill Liners

ABSTRACT

Organoclay obtained from two constituents’ coco-dimethyl benzyl ammonium chloride, and bentonite was used in this study to prepare five admixtures, by varying the amount of organoclay, natural soil, and bentonite. Laboratory experiments were conducted on these admixtures with the objective of identification and assessment of their potential for use in landfill liners. The admixtures had the organoclay ranging from 10 to 25%, and bentonite in the range of 0 to 20%. The admixtures prepared were evaluated by conducting laboratory sorption tests and permeability tests for the determination of retardation coefficient, and hydraulic conductivity. Permeability tests were conducted using consolidation permeameter. Total Organic Carbon (TOC) was determined using TOC Analyzer. Admixture with higher percentage of organoclay exhibits higher organic sorption capacity. Retardation coefficient of the admixtures was determined by curve fitting the experimental data of sorption tests to fit to Freundlich (nonlinear) sorption isotherm. One-dimensional transport simulations were performed to evaluate completely the effectiveness of these materials for use as landfill liner and to develop design charts for determining required liner thickness.