Study on the Content and Species Distribution of Heavy Metal in Sanming Sewage Sludge

For the sewage sludge samples from Sanming Municipal Wastewater Plant in Fujian province, the species and content of heavy metals in sewage sludge and the species distribution of heavy metals were studied. The microwave digestion result showed that the sewage sludge contained Zn, Cu, Pb, Cr, Ni and Cd. The degree of content of heavy metals was Zn>Cu>Pb>Cr>Ni>td. The concentration for Zn, Cu, Pb, Cr, Ni and Cd was 2513.9, 438.6, 152.3, 81.38, 35.1 and 1.6 mg.kg(-1) respectively. Zn exceeded the limited level of the Sludge Agriculture Utilization Standard for acid soil in China, and Zn, Cu and Cd exceeded the third level limited value of Environment Quality Standard for Soils in China. The result of BCR sequential extraction procedure showed that Cr, Ni and Zn in sewage sludge were mainly associated with residual fraction, while Cu, Pb and Cd were mainly in reduced fraction. Zn, Cd and Ni were more active, with potential impact on environment, so more attention should be paid.