PH-dependent leaching behavior of copper, zinc, iron and manganese from municipal sewage sludge

Municipal sewage sludge (MSS) is waste material which remains in waste water treatment plants. This waste residue contains heavy metals such as copper, zinc, iron and manganese, which are considered to Hazardous environmental pollutants. Hence, during the use or disposal of this material in the environment should pay special attention to the fate of contaminants in it. Several experiments to evaluate the risk of waste, including determination of total concentration and heavy metals partition are used. However, numerous studies have shown that this procedures does not provide an appropriate response to the risk level of waste materials. Among the various factors affecting the release and leaching behavior of metals leaching solution pH is considered to the most important factor. The main goal of this research is to obtain an overview of the leachability of MSS produced in a waste water treatment plant of Serkan. PH changes after 48 hours of equilibrium, as well as indicated the buffering capacity of the sludge. The Solubility behavior for copper, zinc, iron and manganese were obtained which are very useful to predicting the leaching behavior in different scenarious. Also, the amphoteric behavior was observed for Cu and Zn. The interesting point was observed for Mn, because after pH 3 Changes in leaching behavior and solubility of Mn was very low. Furthermore, the results showed that the leaching of copper and zinc from sludge is limited due to its natural pH and if the condition is not acidic or alkaline it is not creating any problem.