Fractioning of Trace Metals in Sewage Sludge

The influence of storage time on mobility of chosen heavy metals in sewage sludge by application of Tessier fractioning procedure has been studied. Cr, Pb and Ni were mainly associated to the residual and organic matter fraction and the low mobility for these metals during the storage period has been observed. Zn showed high environmental availability and was associated mainly with reducible, carbonate and exchangeable fractions. The regularity in changes of Cu fractioning during the storage time of sewage sludge was observed. It was stated that transformation of copper chemical forms during the sludge storage takes place and some of Cu species from the organic fraction transformed into exchangeable, carbonate and reducible fractions.