Characteristics of Heavy Metal Species Transformation of Pb, Cu, Zn from Municipal Sewage Sludge by Thermal Drying

Thermal process allow for a significant reduction in the weight and volume of transformed sewage sludge. The high heavy metal content in sewage sludge effectively reduces the possibility of its agricultural use. This study investigated heavy metals transformation from municipal sewage sludge using a combination of thermal drying process. The experiments were conducted using furnace as a heating apparatus to dry the municipal sewage sludge at different temperature and analyze the species of heavy metal in municipal sewage sludge after drying. Results show that the contents of heavy metal are different in municipal sludge. The species of heavy metal obviously transformed after drying at different temperature. Additionally, the transform amount of metals varies in the species of metal as well as the type of heavy metal after drying. The effect of high temperature can transfer the acid-soluble, the reducible and the oxidizable species into the residual species. High temperature has the ability of stabilizing the heavy metals in municipal sewage sludge. (C) 2016 The Authors. Published by Elsevier B.V.