Copper and trace element fractionation in electrokinetically treated methanogenic anaerobic granular sludge.
The effect of electrokinetic treatment (0.15 mA cm(-2)) on the metal fractionation in anaerobic granular sludge artificially contaminated with copper (initial copper concentration 1000 mg kg(-1) wet sludge) was studied. Acidification of the sludge (final pH 4.2 in the sludge bed) with the intention to desorb the copper species bound to the organic/sulfides and residual fractions did not result in an increased mobility, despite the fact that a higher quantity of copper was measured in the more mobile (i.e. exchangeable/carbonate) fractions at final pH 4.2 compared to circum-neutral pH conditions. Also addition of the chelating agent EDTA (Cu2+:EDTA4- ratio 1.2:1) did not enhance the mobility of copper from the organic/sulfides and residual fractions, despite the fact that it induced a reduction of the total copper content of the sludge. The presence of sulfide precipitates likely influences the copper mobilisation from these less mobile fractions, and thus makes EDTA addition ineffective to solubilise copper from the granules.
Subdepartment of Environmental Technology, University of Wageningen, Biotechnion-Bomenweg 2, PO Box 8129, 6700 EV Wageningen, The Netherlands.
Jurate
J
Virkutyte
Eric
E
van Hullebusch
Mika
M
Sillanpää
Piet
P
Lens
D000693:Anaerobiosis; D002118:Calcium / Q000737:chemistry; D002614:Chelating Agents / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods; D003300:Copper / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods; D004785:Environmental Pollutants; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D014131:Trace Elements / Q000737:chemistry*
D002614:Chelating Agents; D004785:Environmental Pollutants; D012722:Sewage; D014131:Trace Elements; D003300:Copper; D004492:Edetic Acid; D007501:Iron; D008274:Magnesium; D002118:Calcium