Speciation and removal of zinc from composted municipal solid wastes

This paper presents composting of the organic fraction of municipal solid w aste containing 50000 mg/kg of cellucotton and 7980 mg/kg of zinc carried o ut under laboratory conditions. In the initial material as well as the comp ost obtained, zinc, cadmium, copper, nickel, and lead were analyzed, and th eir forms were determined by means of sequential extraction. It was found t hat 65% of zinc occurs in the organically bound form. Removal of zinc from the waste through leaching and subsequent electrochemical separation from t he leaching solution was also examined. A double extraction of the waste wi th sodium diphosphate(V) enables a reduction of zinc content to 1240 mg/kg. As a result of electrolysis of the leaching solution, 90.2% of Zn is separ ated on the cathode. This paper suggests a method for processing municipal solid waste with high zinc content based on extraction of the waste with so dium diphosphate(V) and composting. The leaching solution is recovered elec trochemically.