EFFECT OF TRITON-X-100 ON THE RATE OF TRICHLOROETHENE DESORPTION FROMSOIL TO WATER

Continuous-flow stirred tank reactor (CFSTR) experiments and batch sor ption experiments were conducted to determine the effect of Triton X-1 00, soil organic carbon content, and soil/contaminant contact time on the rate of trichloroethene (TCE) desorption from two aquifer soils to water. Soil A and soil B have organic carbon contents of 24 and 1.36% , respectively. TCE desorption from soil A was strongly kinetic, and t he rate of desorption decreased when the soil/contaminant contact time was increased from 1 to 4 wk. TCE desorption from soil B could be app roximated by assuming instantaneous equilibrium between the soil and a queous phases. Aqueous solutions of Triton X-100 at concentrations of 30, 300, and 3000 mg/L increased the rate of TCE desorption from soil A relative to an aqueous solution with 0 mg/L Triton X-100 following b oth 1- and 4-wk soil/contaminant contact times. The increased rates of TCE desorption observed for the 30 and 300 mg/L Triton X-100 solution s are caused by an increase in the mass-transfer coefficient. The incr eased rates of TCE desorption observed for the 3000 mg/L Triton X-100 solutions are caused by the combined effects of an increased concentra tion gradient (resulting from a reduction in the equilibrium sorption coefficient) and an increased mass-transfer coefficient.