Enhancing the use of waste activated sludge as bio-fuel through selectively reducing its heavy metal content

Dewil, Raf; Baeyens, Jan; Appels, Lise

doi:10.1016/J.JHAZMAT.2007.01.100

Title

Enhancing the use of waste activated sludge as bio-fuel through selectively reducing its heavy metal content

Author

Dewil, Raf

Baeyens, Jan

Appels, Lise

Abstract

Power plant or cement kiln co-incineration are important disposal routes for the large amounts of waste activated sludge (WAS) which are generated annually. The presence of significant amounts of heavy metals in the sludge however poses serious problems since they are partly emitted with the flue gases (and collected in the flue gas dedusting) and partly incorporated in the ashes of the incinerator: in both cases, the disposal or reuse of the fly ash and bottom ashes can be jeopardized since subsequent leaching in landfill disposal can occur, or their "pozzolanic" incorporation in cement cannot be applied. The present paper studies some physicochemical methods for reducing the heavy metal content of WAS. The used techniques include acid and alkaline thermal hydrolysis and Fenton's peroxidation. By degrading the extracellular polymeric substances, binding sites for a large amount of heavy metals, the latter are released into the sludge water. The behaviour of several heavy metals (Cd, Cr, Cu, Hg, Pb, Ni, Zn) was assessed in laboratory tests. Results of these show a significant reduction of most heavy metals. (c) 2007 Elsevier B.V. All rights reserved.

Language

English

Source (journal)

Journal of hazardous materials. - Amsterdam

Source (book)

5th European Meeting on Chemical Industry and Environment (EMChIE 2006), MAY 03-05, 2006, Vienna, AUSTRIA

Publication

Amsterdam : 2007

ISSN

0304-3894

DOI

10.1016/J.JHAZMAT.2007.01.100