Effect of acid treatment on the removal of heavy metals from sewage sludge
Ilyas Zhanabayev
Department of Chemistry, School of Science and Technology, Nazarbayev University,
Astana, Kazakhstan
Email: [email protected]
Abstract
With the tightening of the requirements of environmental standards, much attention is focused
on optimizing and improving the methods of sewage and sludge treatment. Since sludge
samples were found to contain significant amounts of heavy metals it must be treated in order
to recycle valuable components by spreading on agriculture land. The present investigation is
an attempt to find optimum conditions of acid treatment to remove heavy metals from sewage
sludge. In the experimental work, sludge samples were subjected to sequential extraction
procedure to determine the concentration of metals heavy metals in each fraction of sewage
sludge. Through a variety of test the optimal concentration of H 2 SO 4 (20%), contact time
(30min) and temperature (80°C) were achieved. The removal efficiency of metals was found
to be, Ni - 74%, Cu - 86%, Cr - 99%, Pb - 11% and Zn - 72%. In addition, changes in the sludge
metal partitioning were investigated.