Remediation of a clay soil contaminated with phenanthrene by using mixture of bentonite and cement

Abstract

This paper investigates the remediation of a clay soil contaminated with phenanthrene, through a series of experimental tests. Mixtures of bentonite-cement (with bentonite to cement ratios of 1:1 and 3:1) at 20% and 30% were used as agents. Unconfined Compressive Strength (UCS) tests were performed on samples with different percentages of agents and curing times. Leaching tests were also conducted on contaminated samples at different curing times by using spectrophotometer apparatus. The results indicated that using the mixtures of bentonite-cement as an agent for natural and contaminated soil leads to an increase in the strength of the soils. The results of leaching tests showed that, for a given percentage of bentonite-cement mixture with different bentonite to cement ratios, the concentration of phenanthrene decreased with increasing the curing time. The bentonite-cement ratio of 1:1 was found to be more effective than the 3:1 ratio in reducing the concentration of phenanthrene. Sensitivity analysis showed that the percentage of bentonite and curing time are more effective in the reduction of phenanthrene than the percentage of cement.