Keren, R., ARO, Israel
Singer, M.J., ARO, Israel

The objectives of this study were to (i) determine the effect of Fe- or Al-polymers on saturated hydraulic conductivity (HC) of smectite-sand mixtures at different percentages of the clay cation exchange capacity (CEC) at different sodium adsorption ratios (SAR) and solution electrical conductance (EC), and (ii) determine the reason for the observed effect. The HC of clay leached with SAR 5 solution decreased with a reduction in solution concentration from 500 to 1 molcm-3, after which clay was leached from the system and HC increased. Little HC reduction occurred at SAR 10 in the presence of hydroxy-Al polymers. At SAR 20,HC of the clay-sand mixtures decreased greatly, but no clay was observed in the leachate. Hydroxy-Fe polymers produced similar effects, but to a lesser extent. Iron was not as effective as Al-polymers in preventing reduction of HC at SAR 10. Additional study results are discussed.