Affiliations: Department of Chemistry, Faculty of Sciences,
University of Damascus, Damascus, Syria | Institute for Hygiene and Environmental Medicine, RWTH
Aachen University, Aachen, Germany | Institute for Biology 1, Unit of Soil Ecology, RWTH
Aachen University, Aachen, Germany
Abstract: A simple analytical method was developed and optimised for the
determination of polycyclic aromatic hydrocarbons in activated sludge
consisting of supernatant and solid, which collected from the aerobic reactor
(aerated zone) of the biological treatment step in a wastewater treatment
plant. The procedure accomplishes in feasible time of extraction and reasonable
solvent volume without the need of any special technique to perform the
extraction step. The method involves extraction of entire sample by sonication
and mechanical shaking using n-hexane, preconcentration by solvent evaporation,
and determination by high-performance liquid chromatography with diode array
and fluorescence detectors. The developed method was optimised to give precise
results in both low and high spiked samples: relative standard deviation lower
than 10%, limits of detection lied between 0.2 and 5 μg kg^{-1},
and recoveries were between 66% and 109%. This method allows the monitoring of
the bioremediation efficiency of PAHs by the activated sludge, since it permits
the extraction of both PAHs; those that adsorbed to the solid phase, and the
other that presented in supernatant phase. The activated sludge could be
valuable in the bioremediation of lighter PAH compounds mainly those which
consist of two and three fused aromatic rings.
