Electrokinetic Remediation of Contaminated Dredged Sediment

Abstract

Abstract This paper investigates the feasibility of electrokinetic remediation of contaminated sediment at Indiana Harbor, Indiana. The sediment is a fine-grained material with high moisture content of 78 % and high organic content of 19 % and it is contaminated with a wide range of polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Four bench-scale electrokinetic experiments were conducted at 2.0 VDC/cm of constant voltage gradient using two surfactants (5 % Igepal CA-720 and 3 % Tween 80), a cosolvent (20 % n-butylamine), and a cyclodextrin (10 % HP-β-CD) as flushing solutions for the solubilization/desorption of PAHs. The mobility and removal of heavy metals was also investigated while flushing these solutions. The experimental results show that 20 % n-butylamine and 5 % Igepal 720 systems are effective for the partial solubilization of the PAHs in the sediments; however, both 3 % Tween 80 and 10 % HP-β-CD systems are found to be ineffective for desorption/solubilization of PAHs in the sediment. None of the selected flushing agents is found to be effective for the removal of heavy metals from the contaminated sediment. The low removal of PAHs and heavy metals is attributed to the high organic content and high acid buffering capacity of the sediment.