In this research, study, a novel liner design was proposed for waste repository sites, constructed wetland
basins and manure management lagoons to prevent the groundwater contamination by seepages from the bottom of
these facilities. For this purpose, sand-bentonite and pumice-bentonite mixtures with pre-defined grain size range
(1.00-0.50 mm) and bentonite content (30%) was used in experiments. Various concentrations of nitrate,
phosphorus (25, 50, 100, 150 and 200 ppm) and heavy metals (Cd, Ni, Pb, Cr and Cu) solutions (10, 20, 30, 40 and
50 ppm) were used to saturate the permeability test samples. Extracts of permeability test were used to investigate
the adsorption and desorption characteristics of proposed mixtures for liner design. With regard to heavy metal
adsorption, bentonite had the best performance. Sand and pumice exhibited similar performances in lead and
cadmium adsorption, but pumice had much better performance than sand in chrome, copper and nickel adsorption.
Although sand-bentonite and pumice-bentonite mixtures exhibited similar performance in nitrate adsorption, again
pumice-bentonite mixtures had much better performance than sand-bentonite mixtures in phosphorus adsorption.
Current results revealed that pumice with macro-micro pore structure and resultant adsorption surface
characteristics could be used as an alternative of sand in liner design.