The presence of polycyclic aromatic hydrocarbons (PAHs) in sediment is a major problem on account of risks associated with the threat to the aquatic ecosystem through bioaccumulation in food chains. For this reason, a process that would be able to degrade sorbed PAHs in sediment would be a question of great interest. The present study aims to assess the treatment efficiency of using chemical oxidation with the following liquid reactants: potassium permanganate (KMnO4), sodium persulfate (Na2S2O8), conventional Fenton, modified Fenton. Since PAH compounds strongly absorbed on the sediment which is considered as a main drawback in application of ex-situ remediation to the sediment of concern, the authors' efforts focused on finding out what liquid oxidant was most effective to obtain maximum acceptable concentration for total 16 PAHs (1000 ng/g) and to assess the optimal reactant doses. The concentration of PAHs in non-treated sediment was around 4226 ng/g (2-ring about 273 ng/g, 3-ring about 1285 ng/g, 4-ring about 1508 ng/g, 5-ring about 789 ng/g, 6-ring about 369 ng/g) and a 76% degradation was required to meet the remediation goals. The efficiency to remove PAHs was 5.3�72.8%, 10.7�39.1%, 0�30.9% and 31.5�68.3% for KMnO4, Na2S2O8, conventional Fenton and modified Fenton, respectively. Study results demonstrated a medium reduction in sediment sorbed concentration for a mixture of 16 PAHs; only in case of using KMnO4 showed the highest removal efficiency (72.8%) with a considerably large amount of oxidizer being used. The removal efficiency with the use of modified Fenton showed the remarkable improvement in comparison with the conventional Fenton. Among chelating agents, sodium citrate resulted in the maximum contaminant removal through H2O2 activation at near neutral pH environment. The usage of sodium pyrophosphate and sodium oxalate with the higher amount can cause negative effect on removal efficiency. In general, the degradation of PAHs in slurry system through this study was limited, which can be explained by several reasons: PAHs availability, PAHs reactivity and sediment composition.

Feasibility of using chemical oxidation for remediation of PAHs contaminated sediments

248th National Meeting (2014)

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