Removal of Heavy Metals in Municipal Sludge by Using Acetic Acid-H2O2- Ferrite Way

Removals of copper and zinc from municipal sludge from Tianjin Dongjiao Sewage Treatment Plant by using acetic acid - H₂O₂ way and the removals of heavy metals from municipal sludge extract fluid by using improved acetic acid- ferrite way were studied in experiment. The better technique condition to remove copper and zinc was that the quality concentration of acetic acid was 2 mol/L, the ratio of sewage sludge, H₂O₂ and acetic acid was 1:2:50, the reaction time 4 hours in room temperature, and the removal rates of copper and zinc were over 95%. Using improved ferrite way and lime milk as neutralization, Cu, Zn, Cr, Ni, Cd, Pb could be removed from municipal sludge filtrate caused by acetic acid- H₂O₂, the removal rates of Cu, Zn, Cr, Ni, Cd, Pb were 94%, 98 %, 86 %, 92 %, 89 %, 99 % and the filtrate could be dicharged legally. The best technique condition was that the initial concentration of FeCl₃ /FeSO₄ was 0.10/0.05 mol/L, the added Fe²⁺:Fe³⁺ (mol value) = 1:2, Fe³⁺/Mⁿ⁺ (Cu²⁺,Zn²⁺) = 10, the pH value was 9, reaction temperature was room temperature.