Determination of sixteen polycyclic aromatic hydrocarbons in aqueous and solid samples from an Italian wastewater treatment plant

Abstract

This study addresses the issue of whether it is possible to accurately predict the removalefficiencies of metals of environmental concern (i.e., Al, Ag, As, B, Ba, Cd, Cr, Fe, Mn, Hg, Ni,Pb, Cu, V, and Zn) in a wastewater treatment plant. The plant in question (at Fusina, Venice,Italy) is fed by mixed wastes from municipal and industrial sources (300 000 equivalentinhabitants) and discharges the treated effluent into the Venice lagoon. The year-long samplingcampaign (2001-2002) yielded a substantial amount of analytical data and relatively wide rangesof concentrations of metals in the influent samples, which made it possible to study the removalefficiencies by plotting the terms (inlet concentration - outlet concentration) vs (inlet concentration)for each metal investigated. The data in the plots were fitted using the linear regressionmodel Y ) BX. The slope rates (terms B), which were estimated by the least-squares method,have been adopted as the removal efficiencies, and they can be considered as constants in theconcentration ranges recorded in this work. The relative abundance of metals in the rawwastewaters feeding Fusina WWTP followed the order Al > Fe > B > Zn > Ba > Mn > Cu >Pb > Hg ) Ni > Cr ) As > V > Ag > Cd, while in the effluent the order was Fe > Al > Zn >Mn > Ba > Ni > Cu > Pb > Cr > Ag > As > Hg ) V > Cd. The removal percentages (%) of themetals were Al ) 92 ( 1; Ag ) 94 ( 1; As ) 76 ( 3; B ) n.d.; Ba ) 85 ( 2; Cd ) 85 ( 2; Cr )87 ( 1; Fe ) 90 ( 1; Mn ) 61 ( 2; Hg ) 93 ( 1; Ni ) 50 ( 3; Pb ) 92 ( 1; Cu ) 93 ( 1; V )74 ( 2; and Zn ) 75 ( 3.