The report presents the results of selected heavy metals (Zn, Cu, Cd, Ni, Pb) removal from industrial wastewater sludge collected from metallurgy industry. As washing solutions two chelating agents were used: EDTA and citric acid. The study was focused on 0.000 (deionized water), 0.010, 0.050, 0.075, 0.100 M and 0.000, 0.050, 0.100, 0.500, 1.000 M, EDTA and citric acid solutions, respectively.

Efficiency of EDTA and citric acid solutions for metal removal was studied by extraction of sludge samples with chelators. Chemical extraction of selected metals was effective for both types of solution. Optimal concentration of EDTA was 0.100M for Zn, Ni and Cd, 0.075 M for Cu and Pb. Optimal concentration of citric acid was 0.500 M for all analyzed metals