Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

摘要

Experiments were carried out to study the removal of heavy metals from municipal sewage sludge sludge by proper method for land application. The sequential extractions for metal fractionation showed that the non-digested sludge from Guangzhou contained Cu and Zn principally bound to carbonate and oxides and the metal sulfides were low. Among H_2SO_4, EDTA and NH_4HCO_3 extractant agents H_2SO_4 was the most efficient and economic in removing the heavy metals, Especially with the addition of the concentrated acid.