Factors affecting the removal of metals during activated sludge wastewater treatment I. The role of soluble ligands

Autor: P. S. Lawson, John N. Lester, Robert M. Sterritt
Rok vydání: 1984
Předmět:
Zdroj: Archives of Environmental Contamination and Toxicology. 13:383-390
ISSN: 1432-0703
0090-4341
DOI: 10.1007/bf01056253
Popis: Samples of mixed liquor were withdrawn from a laboratory-scale activated sludge simulation operated at a range of sludge ages from 3 to 12 days in order to examine the difference in metal uptake by the mixed liquor biomass in the absence and presence of soluble ligands. One half of the samples were centrifuged, washed, and resuspended in physiological saline solution, and the rest were left unchanged. In another experiment, aliquots of synthetic sewage were added to mixed liquor samples to investigate the effect of increased soluble influent sewage ligands on metal uptake. It was found that at low sludge ages, uptake of metals by biomass was lower in the presence of soluble ligands than in their absence, but as the sludge age increased uptake in the presence of soluble ligands also increased. It is suggested that at low sludge ages, ligands predominantly prevented metal uptake by the biomass by chelating the metals and stabilizing them in solution and, at longer sludge ages, ligands predominantly enhanced uptake. Increasing the concentration of synthetic sewage caused a reduction in metal removal and it is suggested that soluble ligands in the synthetic sewage were responsible for preventing metal uptake.
Databáze: OpenAIRE
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