The concept of a sorption chemical barrier for improving effectiveness of landfill liners

Abstract

In this work, we apply the concept of a "sorption chemical barrier", as a means of improving landfill liner effectiveness. The sorption barrier is formed by addition of the organoclay hexadecyltrimethylammonium-montmorillonite (HDTMA-montmorillonite) to a fine sand-bentonite liner. Using previously published experimental data and mathematical model simulations, we demonstrate that such a liner retards significantly the transport of landfill leachate components, thus, increasing the useful life of the liner by a factor of 5 to 10, for the cases calculated. The superior HDTMA-liner performance is maintained even when the sorption extent is significantly decreased, as in the case of leachate containing methanol, a cosolvent miscible with water, found in some industrial and hazardous waste sites. The increase of the useful life of the liner results in smaller liner thickness, required to provide equivalent protection, from the point of view of contaminant transport, as compared to the liner containing no organoclay. (Clay liner design based on hydraulic conductivity alone neglects the early breakthrough due to hydrodynamic dispersion and, therefore, is not a conservative one.

Organo/LDH nanocomposite as an adsorbent of polycyclic aromatic hydrocarbons in water and soil–water systems

“…where K d-soil and K d-HT-DDS are the distribution coefficients for PAHs adsorption on soil and HT-DDS, respectively, and  soil and  HT-DDS are the respective mass fractions of soil and HT-DDS in the mixture [39][40][41].…”

Modification of clay barriers with a cationic surfactant to improve the retention of pesticides in soils

“…K values were determined according to the equation proposed by Voudrias [31]: K = θ soil K soil + θ barrier K barrier , where θ soil and θ barrier are the respective fractions of natural soil and natural clay or organo clay/soil in the columns, and K soil and K barrier are the respective adsorption constants of linuron, atrazine and metalaxyl by the natural soil and by the different natural clays or organo clays/soil comprising the barriers of the columns. These adsorption constants (K soil and K barrier ) are included in Table 3 and they were taken from previous works by the authors [17,27] where the adsorption of various pesticides by different natural and organo clays/soils, including those selected in this work, were studied from adsorption isotherms in batch experiments.…”

Development of reactive artificial liner using recycled materials. 2. Chemical transport properties

“…(1) upper boundary condition C(0,t) = C o when t ≥ 0; (2) lower boundary condition C(∞,t) = 0 when t ≥ 0; and (3) initial condition C(z,0) = 0 for z ≥ 0 (Foose, 2002;Lo, 2003;Voudrias, 2002): (1) upper boundary condition C(0,t) = C o when t ≥ 0; (2) lower boundary condition C(∞,t) = 0 when t ≥ 0; and (3) initial condition C(z,0) = 0 for z ≥ 0 (Foose, 2002;Lo, 2003;Voudrias, 2002):…”