Experimental Investigation of Phenanthrene Pollutant Removal Efficiency for Contaminated Sandy Soil by Enhanced Soil Washing


Polycyclic aromatic hydrocarbons (PAHs) are environmental concerns that must be removed to acceptable level. This research assesses two agents (Na2EDTA and SDS) to remediate contaminated sandy soil, spiked with 500mg/kg phenanthrene. Five sets of experiments (batch) are applied to investigate the optimal of five influencing factors on soil remediation: Na2EDTA-SDS concentration, liquid/Solid ratio, stirring speed, pH value of flushing solution and mixing time. The results of batch experiments showed that SDS has high phenanthrene removal efficiency (90%), while Na2EDTA shows no phenanthrene removal. pH has no effect on phenanthrene removal. To study the influence of flow rates on the removal efficiency of contaminants, two column tests with hydraulic gradient of 0.2 and 1.2 conducted by SDS solution. The results illustrate that high phenanthrene removal from soil obtained by 1.2 hydraulic gradient condition. The SDS flushing solution removed approximately 69% and 81% of phenanthrene from soil under low and high hydraulic gradients, respectively. It was concluded that phenanthrene removal depend on surfactant micelles formation. Overall, the study showed that soil flushing removal efficiency for contaminants depends on the flushing agents selectivity and affinity to the contaminants and the condition of hydraulic gradient