The Effect of Phytoremediation and Bioaugmentation on the Removal of Phenanthrene and Pyrene from Contaminated Soil

In this study, the efficiency of phytoremediation on soils contaminated by Phenanthrene and Pyrene as well as the impact of bioaugmentation and nonionic surfactant Tween80 on its performance was evaluated by sorghum and Onobrychis sativa. Soils collected from the pastures of Kohkiluyeh and Boyerahmad province in Iran, with concentrations of 100 and 300 mg per kg of Phenanthrene and Pyrene, which were separately and combined (9 levels) contaminated, and 1.5 kg of soil was poured in each pot in different conditions of natural, bioaugmented and surfactant separately and combined (12 cases), were a total of 108 cases, with three replications (324 pot) for 120 days were considered in a similar condition to the field. At last, the concentration of Phenanthrene and Pyrene of soil samples was measured by HPLC to determine the amount and rate of removal. Also, microbial population of soil and Rhizosphere was counted. The results showed that both plants significantly improved the removal of Phenanthrene and Pyrene from soil. Bioaugmentation and nonionic surfactant Tween80 increased the removal efficiency. In the composition of plants, bioaugmentation and the surfactant showed significant increase, so as removal of 99.4% and 98% for Onobrychis sativa, and 96.5% and 99% with sorghum were achieved for the Phenanthrene and Pyrene, respectively. The study showed that both sorghum and Onobrychis sativa had a good performance in phytoremediation of contaminated soils by Phenanthrene and Pyrene, and addition of bioaugmentation and surfactants improved the removal of Phenanthrene and Pyrene to nearly complete.