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.

Improving the permeability and adsorption of phenol by organophilic clay in clay liners

“…It is also proposed that the presence of bentonite reduces hydraulic conductivity of admixture. The same trend was observed by Jhamnani et al [2], who obtained the best permeability coefficient (1.6 × 10 -10 m/s) at the same mixing percentage. Various factors can influence hydraulic conductivity, which will also be the cause for different results across different studies.…”

“…This observation could be attributed to the shrinkage of Montmorillonite structure [41]. In the other researches performed by Irene [7] and Jhamnani [2], the permeability of TOC-contaminated solutions was studied. Their reported permeability coefficients were 0.4 × 10 -8 and 1.8 × 10 -8 (cm/s), respectively.…”

“…In addition, the best adsorption of Total Organic Carbon (TOC) was obtained for sample containing 20% organophilic clay and 80% sand. Jhamnani [2] also reported a permeability of 1.6 × 10 -8 cm/s for a sample with 20% bentonite, 20% organophilic clay and 60% sand. He also asserted that the highest adsorption capacity of TOC was allocated to a sample with 15% bentonite, 10% organophilic clay and 75%.…”

“…The retardation factor (R) illustrates the effect of retarding the transfer of pollutant in the adsorption process. The adsorption level of organic contaminants by natural soil and clay depends on their solubility and the organic carbon content [2]. In organophilic (modified) clay, ion exchange process leads to convert ordinary bentonite to modified one.…”

Geotechnical and Geochemical Assessments of Shales in Anambra Basin, Southeastern Nigeria, as Landfill Liners

“…The use of landfills to contain MSW is a common waste management practice and one of the cheapest methods for organized waste management practices in many parts of the world (Dsakalopouos et al 1998;Jhamnani and Singh 2009;Longe and Balogun 2010). The performances of landfills depend greatly on their impact in the environment, so it is important to design adequate control to protect public health and the environment.…”