Study on Variation Trends of Heavy Metals Contents in Process of Sludge Energy Utilization

Abstract

Application of sludge-to-energy is an important direction for disposal of sludge, and it is necessary to provide the contents change of heavy metals in sludge. Through sampling in situ and analysis in laboratory, distributions of seven heavy metals in five kinds of sludge, which were come from wastewater treatment plant of Jilin Petrochemical Company of Petro China, were studied, and contents change of heavy metals in the course of sludge-to-energy were analyzed. The results were compared with the other sludge in the factory and municipal wastewater treatment plants and the national standard. The results showed that the heavy metal contents are different in the different sludge, and the mean is Fe>Cu>Zn>Mn>Pb >Cr>Cd, the total content distributions from high to low is incinerated sludge, chemical sludge, activated sludge, neutralization sludge, digested sludge. Contents of Cu and Zn exceeded the the mean of 44 municipal wastewater treatment plants and GB18918-2002. After biogas of digested sludge and energy of incinerated sludge were recovered, heavy metal contents exceeded in varying degrees, which were paid more attention for treatment and utilization.