First Comprehensive Analysis of Potential Ecological Risk and Factors Influencing Heavy Metals Binding in Sewage Sludge from WWTPs Using the Ultrasonic Disintegration Process

In this study, the occurrence, fractionation, and potential ecological risk associated with seven heavy metals (HMs), i.e., Cd, Cr, Cu, Ni, Pb, Zn Hg in sewage sludge (SS) were investigated. The main aim of study was to conduct first comprehensive analysis HMs SS collected from two municipal wastewater treatment plants (WWTPs) using ultrasonic disintegration (UD) thickened excess aimed at improving effects anaerobic digestion (AD). order assess level risk, groups indices related total content their chemical forms used. For purpose, a modified BCR sequential extraction conducted. obtained results revealed that according values indices, highest posed by Cu (and lesser extent Ni Cr), while relation speciation Zn, Cd some cases Cr). general, indicated beginning (primary SS) final stages processing (digested dewatered SS). This means may strongly depend on processes used WWTPs especially AD, dehydration activated process, as well characteristics raw wastewater. statistical balance sheets key factors which influence way bind are: pH, TOC, OM Eh. showed UD does not cause any significant changes concentrations SS, release into supernatant mobile forms. proves is safe environmentally friendly method pretreatment.