Title: Analysis of Chemical Speciation and Bioavailability of Heavy Metals in Waste Activated Sludge During Anaerobic Digestion
Abstract: The major limitation of land application of sewage sludge is the total heavy metal contents and their bioavailability to the soil-plant system.This study was conducted to determine the heavy metal speciation and the influence of changing the physical-chemical properties of the medium in the course of anaerobic digestion on the concentrations,bioavailability or chemical forms of Cu,Zn,Cr and Ni in sewage sludge.Principal physical and chemical properties of sewage sludge during anaerobic digestion were investigated.The total metal contents in digested sludge were higher than that in raw sludge but lower than the limit values of land application.Furthermore,it was observed by using Tessier sequential extraction procedure in sludge during anaerobic digestion that heavy metal distribution and bioavailability show some changes depending on the metal itself and the physical-chemical properties of the medium.Bioavailable fractions of all elements tend to decrease.Cu and Cr present more affinity to organic and residual fractions,while Zn and Ni seem to be preferentially bound to all fractions except exchangeable.Significant degrees of correlation were found between certain heavy metal fractions and changes of some selected variables(e.g.pH,VS/TS,alkalinity and ammonia)during the course of anaerobic digestion.
Publication Year: 2012
Publication Date: 2012-01-01
Language: en
Type: article
Access and Citation
Cited By Count: 3
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot